DELIVERABLE B.2.1
PROCEDURE FOR PRINTING
SUSTAINABLE COMMERCIAL BAGS
This document is the proposal developed by the Consortium of ECOFLEXOBAG project. The
final document will be developed after the completion of the demonstration tests and
assessment of validation conclussions.
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1. INTRODUCTION
2. METHODOLOGY
2.1 Structure
2.2 How to use this document
3. TECHNICAL BASES OF FLEXOGRAPHY
3.1 Flexography Printing System
3.2 Flexographic Printing Process
3.3 Materials used in the flexographic printing process
 3.2.1 Printing substrates
 3.2.2 Inks
3.4 Plastic Bags BATS
4. STEP BY STEP PROCEDURES
4.1 Pre Conditions
 4.1.1 To ensure regular internal communication
 4.1.2 Working on external communication and support
 4.1.3 Implementing a quality control system
 4.1.4 Checks on the harmfulness / hazardous nature of materials and additives
 4.1.5 ‘Technical’ update
4.2 Design
 4.2.1 Properly specify the digital file for printing
 4.2.2 Use process and mechanical control elements
 4.2.3 Colour Conversion (using ICC Profiles)
 4.2.4 Checking digital files “Pre-flight”
4.3 Color Proof
 4.3.1 Producing the colour proof
 4.3.2 Control of Colour Proof
4.4 Printing Form
 4.4.1 To determine proper specifications
 4.4.2 Control Environmental Conditions of Printing Form
4.5 Anilox
 4.5.1 To select the optimum anilox specifications
 4.5.2 To control the environmental conditions of the anilox
4.6 Plate Mounting
 4.6.1 To control the critical features of the adhesive tape
 4.6.2 To control the critical features of sleeves
4.7 Ink Formulation
 4.7.1 To control raw materials
 4.7.2 To specify the critical formulation parameter
4.8 Press Optimization
 4.8.1 Variation of Print Process Parameters
 4.8.2 Determination of Optimum conditions
 4.8.3 Producing the ICC Profile. Fingerprint
4.9 Printing
 4.9.1 Machine Set Up
 4.8.2 Production of OK print
 4.8.3 Control of printing production
4.10 Resources Efficiency Management
 4.10.1 Waste management
 4.10.2 Energy efficiency
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 4.9.3 Water efficiency
 4.9.4 Horizontal issues
 4.9.5 Implementation of 5S
ANNEXES
ANNEX. TEST FORM AND WORKSHEETS
ANNEX X. SUMMARY OF SUSTAINABLE PRINTING PROCEDURE
ANNEX. FLEXOGRAPHY INKS PROPERTIES
ANNEX. QUALITY CONCEPTS IN FLEXOGRAPHY PRINTING
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1. INTRODUCTION
ECOFLEXOBAG Project (LIFE11ENV/ES/000646_Development and Demonstration of Best
Practices to Design and Produce Sustainable Commercial Bags) is a LIFE+ funded European
project that aims at reduction of negative environmental impact of Plastic Commercial Bags
during their entire lifecycle. Its main objective is to develop an innovative methodology that
will help bags manufacturers, particularly small and medium enterprises, to design and
produce environmentally sustainable Plastic Commercial Bags.
There exist different alternatives which could be used by the Plastic Commercial Bags
manufacturers in order to reduce the impact of their products through their Life Cycle,
according to the legislative and market trends like Sustainable substrates, Printing Best
Available Techniques and Production of reusable/degradable bags. However the implantation
of these alternatives is low and/or incorrect due to several different limitation implantation
factors that the manufacturers must faced:
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Lack of life cycle approach in the design of sustainable commercial bags. So, the best
sustainable are not adopted in each case.
Lack of knowledge about the physical properties and production behaviour of the new
sustainable substrates. So, there exist some production or quality problems in the
product which don´t allow manufacturers and end users to fully adopt these materials.
Technical problems when implementing Printing Best Available Techniques in
combination with new sustainable substrates. These technical problems became in a
reduction of quality and productivity and finally they are abandoned
Lack of process monitoring, poor quantification of environmental impacts, which
becomes in a lack of knowledge about the fulfillment of legislative requirements, the
associated costs and the impact on the quality and productivity. Then, the
implantation of environmental solutions is not controlled and finally they are
abandoned
ECOFLEXOBAG will develop an innovative methodology for design and production of
sustainable Commercial Bags, including;

Best practices for designing sustainable commercial bags
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Best practices for implementing BATs with new sustainable substrates

Best practices for monitoring the sustainable production of commercial bags
These best practices will be adapted to an Online Tool which will allow the Commercial Bags
manufacturers to implement them in the most effective way.
Objective; This document “Deliverable B.2.1 Procedure for Printing Sustainable Commercial
Bags” aims to give guidelines to the bags manufacturers in order to optimize the printing
quality when combining the suitable Best Avalilable Techniques and sustainable substrates.
According to the conclussions obtained in Action A.1, the guidelines are focused in the use of
water based inks as alternative to solvent based inks.
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2. METHODOLOGY
2.1 Structure
This document “Deliverable B.2.1 Procedure for Printing Sustainable Commercial Bags” is
structured in the next parts;
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Introduction: aiming to contextualize the development of the document.
Methodology; aiming to explain the structure of the document as well as how to use
it.
Technical Bases of Flexography; aiming to make a brief overview of the printing
system and material used for the production of plastic commercial bags in order to
increase the technical knowledge of the bags manufacturers about the technical
aspects driving the bags production.
Plastic Bags BATs; aiming to make a brief overview about the environmental
properties of the Best Available Techniques applicable to the production of bags
manufacturers in order to increase the technical knowledge of the bags manufacturers
about the environmental aspects of their activity and suitable alternatives..
Printing Bags Processes; aiming to make a brief overview of the processes involved in
the printing of Plastic Commercial Bags, in order to increase the technical knowledge
of the bags manufacturers about the technical aspects driving the bags production.
Print Quality in Flexographic Printing; aiming to make a brief overview of the
parameters and activities related with the Printing Quality of Plastic Commercial Bags,
in order to increase the technical knowledge of the bags manufacturers about the
Quality Control.
Step by Step Procedures; including all the activities needed to ensure an optimal
printing with water based inks and sustainable substrates, organized “step by step” in
order to give to the bags manufacturers the essential information
The content of this document has been developed based on the experience related with
flexographic printing of the partners of ECOFLEXOBAG, especially AIDO with the main
contribution of AIMPLAS and VTT as well as the rest of partners of the Consortium, following
the next steps.
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Evaluation of bases of flexographic process and impact of Water Based Inks and
Sustainable Substrates in the quality and productivity.
Evaluation of the applicability of Printing Standard Procedures to the printing with
Water Based Inks and Sustainable Substrates
Proposal, discussion and agreement of the index of the Procedure for Printing
Sustainable Commercial Bags
Development of Procedure for Printing Sustainable Commercial Bags
It has been also used information obtained in Action A.1 of ECOFLEXOBAG.
The knowledge and work of the partners of ECOFLEXOBAG has been completed with the use of
some external information. Direct information has been obtained through an External
Assistance of Welsh Centre for Printing and Coating (WCPC) and indirect information has been
obtained through different scientific and technical bibliography (see References).
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3. TECHNICAL BASES OF FLEXOGRAPHY
3.1 Overview of Flexographic Printing System
The principle of a flexographic printing unit can be seen in Figure 3.1 There are many variations
on the basic flexo press, each developed for a specific purpose.
Figure 1 Schematic figure of a flexographic printing press unit equipped with a chambered doctor blade inkmetering system
The transfer of ink to the substrate is one of the most important factors affecting the quality of
the final printed result. The thin, highly fluid and rapid-drying ink used in flexography requires
the use of an ink-metering anilox roller, which is engraved with a cell pattern, to enable an
even and fast ink transfer to the printing plate. The configuration of the cells in the anilox
roller, the pressure between the rollers and the use of a doctor blade mechanism controls the
amount of ink retained in the anilox roller and therefore available to be transferred to the
printing plate.
The flexographic printing plate, or cliché, which is mounted on the printing cylinder, is either
made of rubber or more commonly of a photopolymeric material. This flexible printing plate
enables good quality printing even on rough substrates. It is a relief printing process meaning
that the image area on the printing plate is raised above the non-image area. The image area
receives the ink, which is transferred to the print substrate when the substrate is pressed with
support of the impression cylinder against the printing plate. Flexography is a direct method,
i.e. the printing plate transfers the ink directly to the substrate, and the image on the printing
plate is therefore inverted. The pressure between the anilox roll and the printing plate, and
then between the printing plate and the substrate, must be carefully adjusted to give a
uniform print with no areas of over impression.
Both sheet-fed presses and web presses are used in flexographic printing. The most popular
type of press is the central-impression/satellite press where two to eight printing units are
arranged around the single central impression cylinder. The other basic types of flexographic
presses are stack and inline presses1.
1
Maria Rentzhog. YKI, Ytkemiska Institutet AB. 2004. Characterisation of Water-Based Flexographic Inks and their
Interactions with Polymer-Coated Board
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3.2 Flexography printing processes
The processes involved in the printing of Commercial Bags are usually the next;
3.2.1 Design
In our competitive customer driven society, the functions of Commercial Bags design must be
able to sell the brand and product at the same time, while creating image and customer
perception and ensuring the required structural properties. It is the elements of a package that
influence consumers' decision making process and can determine their choices. Thus a well
designed packaging is evaluated as a competitive advantage.The design process refers to the
planning and managerial work that is needed to form a product or corporate communications
such as Commercial Bags. The design process of Commercial Bags is a very important part of
creating the product, but package designers are often overlooked or called in too late in many
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companies and/or they don´t have information/knowledge for satisfying the production
requirements defined by the printing systems and materials to be used. The design of the
image to be printed has a critical impact on the success of the print process. Incorrectly
prepared digital artwork will result in a job that may be impossible to replicate and incorrect
manipulation of the file can result in corruption of all or part of the image2.
3.2.2 Color Proof
The colour proof is an important document in the bag production process as it sets out the
customer’s expectations of the graphic image reproduction. In the production of sustainable
bags this may take many forms dependent upon the expectation of the customer and the
value of the job. A high value high quality production run may require a full on press contract
proof but in many cases an on screen display may be sufficient e.g. for on-line orders. The
customer and printer should be clear about their requirements and tolerances and agree on
these before commencing design. The colour proof may pass through several stages through
the production of the design or may remain at an agreed level rather than proceeding to full
press proof. In early stages, a concept proof can be produced, it is usually not profiled and not
used for matching colour but does communicate the design concept. The next stage is the
colour target proof, it is not profiled but does represent the expectations for colour
reproduction. The top level of proofing is the Profiled Contract Proof which is an accurate
representation of the graphic reproduction from the production press.
3.2.3 Printing Form Production
There are different methods for the production of flexo plates including laser engraving and
photopolymer processing. However, all flexographic plates have common characteristics. The
image is created on the plate in relief with the raised areas of the plate accepting ink from the
anilox roll and transferring it to the substrate. The plate is made up of a flexible deformable
material that is applied to a cylinder using a sleeve of backing tape. The flexibility of the plate
allows for deformation of the plate dots through the print nips. A positive engagement is
applied in the printing nip which is taken up by expansion and barrelling of the plate dots,
which along with ink squeeze, causes dot enlargement compared to the area of the plate dot.
Types of flexo printing forms (Liquid/Solid); Photopolymer plates can be produced from liquid
or solid photopolymer. In the case of solid plates they are supplied in sheet form and a mask
applied or laser ablated, UV light is then used to cure the plate. In the curing process a back
exposure hardens the entire plate area and sets the relief depth. The front exposure then
hardens the image areas through the mask. Unexposed polymer is washed from the plate
using wash up chemicals or water and disposed of as waste. Liquid photopolymer plates are
processed in much the same way except that liquid photopolymer is applied to the negative
before exposure. Following exposure unused photopolymer remains liquid and can therefore
be recycled, hence reducing waste.
Structure of flexo printing forms (Sheet/Sleeve); There are two structures of flexographic
plate in use, sheet systems and sleeves. Sheets are the original method for the production of
flexographic printing plates. Sheets of raw material are processed to form the image in relief
2
Blekinge Institute of Technology, 2013. Perspectives on the Elements of Packaging Design. A
Qualitative Study on the Communication of Packaging
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on the plate. The flat sheet is then wrapped around a steel cylinder attached with double sided
mounting tape.
Sleeve plate systems are made in the round on a tubular sleeve, the sleeve then slides onto a
cantilever cylinder on the press. Sleeve systems have advantages over sheets as they avoid the
need to have a separate plate mounting system. The lightweight sleeves are also easier to
handle potentially reducing the need for multiple operator or hoists for mounting on press.
3.2.4 Anilox Production
The anilox is the engraved cylinder which meters the volume of ink supplied to the plate and
therefore the substrate. Mechanically engraved anilox rolls are produced by forcing an
engraving tool into the surface of the roll to produce the cell pattern, this can then be chrome
plated to harden the surface. Mechanically engraved anilox rolls are used when a low screen
count high volume transfer is needed however the majority of anilox rolls used are now laser
engraved ceramic rolls. A coating of ceramic is applied to either a steel base or sleeve and cell
created by evaporating the ceramic using laser technology. As laser technology developed the
ability to produce accurate and repeatable engravings with different cell geometries, It is now
possible for anilox rolls to be engraved accurately and repeatability with cell counts up to
1800lpi
3.2.5 Ink Formulation
Praparation of the Ink, including appropriated content of solvent or water and additives
matching the requirements in terms of quality and productivity
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3.3 Materials used in the flexographic printing process
3.3.1
Printing substrates
Flexographic printing is distinguished from other print methods by the variety of substrates
that can be printed on and it is therefore a central process in packaging printing, next to
gravure and offset printing. The packaging market can be divided into flexible packaging
(paper, film and foil), multi-wall bags, corrugated and pre-printed linerboard, labels and
wrappers, folding cartons, beverage carriers and cans. The choice of printing substrate is in
most cases determined by the end application and the requirements demanded by it. Printing
substrates can be grouped into five categories, namely paper and paperboard, corrugated
board, laminates, foils and films.
ECOFLEXOBAG Project is focused in commercial bags produced with plastic films. The common
single use polyethylene bag, is the lightweight, plastic, carrier bag used in most supermarkets
and provided free of charge until some years ago. It is a vest-shaped bag and has the
advantage of being thin gauged and lightweight. They are usually manufactured in high or low
density polyethylene (HDPE or LDPE). It has been also termed as “disposable”. These
materials are the most used in bags manufacturing, so they are considered to be included
within the scope of the project because that any feasible improvement in terms of
sustainability (use of recycled plastic of energy savings, for example), can suppose a large
effect taking into account the great number of companies in Europe using this material for
manufacturing bags and as a consequence the global effect in environmental impact.
The plastic materials to be considered when producing more sustainable plastic bags are:
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Oxo-degradable (LDPE/HDPE). Oxo-degradable polyethylene is included within the
scope of the project because is a widely used technology in an important segment of
market, but there are several uncertainties related to this technology that should be
clarified.
Bio-based (LDPE/HDPE). This material is selected because although its presence in
market is still very limited, it is a trend that surely will have increasing interest during
next years.
Compostable materials (based on starch, PLA and polyester). These bags are the only
visible presence of compostable material in market. As they have recently started to
be available for consumers, and considering a possible increasing of these bags in
market in next future.
Recycled plastics; secondary raw materials coming from mechanical recycling of
plastic waste
As a general conclusion it can set that, regardless of the type of plastic material used, the
plastic bag with the least amount of environmental impacts would have the following features:
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Reusable,
Made from recycled plastics, and
Lightest weight possible.
Therefore, the suitability of these materials should be analyzed in terms of their specific use,
possibility of recycling content and/or reusable capacity.Further information about
sustainability of printing substrates is available in Deliverable B.1.1 “Procedure for design
sustainable Commercial Bag” (4.3.1.2 Selection of low impact materials).
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3.3.2 Inks
The nature and demands of the printing process and the application of the printed product
determine the fundamental properties required by flexographic inks.
A functional flexographic ink must exhibit several qualities. It needs to produce a color or other
visual effect. It must adhere to the material being printed (the substrate). It must withstand
conditions to which it will be exposed in practical use, such as chemicals, abrasion, and
extreme temperatures. Finally, it needs to produce a consistent finish.
Different types of ingredients contribute to a successful ink. Five types of components allow
ink to adhere to a substrate and produce its visual effect. The solvent provides fluidity, which
allows the ink to be transported from the ink fountain to the substrate. The colorant, which
can be either a pigment or dye, provides the color associated with ink. The resin causes the ink
to adhere to the substrate, among other traits. Additives modify the physical properties of the
inks, such as flexibility and the coefficient of friction.
Solvents; Solvents are important in delivering the ink to the substrate. The solvent allows the
ink to flow through the printing mechanism, and then evaporates so that the ink forms a solid
coating on the substrate. Typically, inks are manufactured and transported in a concentrated
form, and the printer must add solvent to the ink to attain the desired viscosity. A solvent must
display several important characteristics. It must adequately disperse or dissolve the solid
components of the ink, but must not react with the ink or with any part of the press. It must
dry quickly and thoroughly, and have low odor. Finally, it is desirable for the solvent to have
minimal flammability and toxicity concerns.
Common solvents in solvent-based inks include ethanol, propanol, and propyl acetate. In
water-based inks, the solvent is water, which is amended with alcohols, glycols, or glycol
ethers. UV-cured inks are different in that they do not have solvents per se, in that the
chemicals are not added with the intention of being evaporated after application of the ink.
Fluidity is provided by liquid, uncured components of the ink, such as monomers, which are
incorporated chemically into the ink upon curing, instead of evaporating3.
For environmental and health reasons the use of traditional organic solvents has gradually
been replaced by water and non-volatile products. In the context of the production of Plastic
Commercial Bags within ECOFLEXOBAG Project, solely water-based inks are considered
because UV Curing are not applicable to Bags Production.
The main focus of substitution of solvent based inks has been replacement with water based
ink. Water-based ink, where the solvent content is replaced with water, has the advantage of
significantly reducing solvent content although water based inks will typically contain a small
proportion of solvent. Further solvent reduction is achieved through the use of water-based
cleaners however in practice solvent cleaners are often used, especially where inks have dried.
As water has a lower volatility than solvents used in inks, the drier power requirements are
higher which can limit production speed for existing installations. The higher power
requirements are however off set due to removing waste gas treatment and the ease of
recirculation to the facility. Water-based inks are often less flammable than solvent-based inks
and are thus easier to store and use.
Figure 3.3 shows a summary of operational advantages and disadvantages of different ink
technologies
3
EPA 2002. Flexographic Ink Options: A Cleaner Technologies Substitutes Assessment
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Ink Technology
Solvent
Water-based
Advantages
Disadvantages
Viscosity monitoring and adjustment.
Highly flammable.
Established technology.
VOC extraction and treatment.
Wide
range
of
substrate Environmental concerns.
compatibility.
Cleaning with aggressive chemicals.
Presses must be certified as solvent safe.
Rolls must remain wet i.e. rotate constantly
Higher dryer power.
Low VOC content.
Film substrates may require pre-treatment.
Clean up with water.
Plugging of cells.
Production speed and quality
Build up on flexo plate – mid run cleaning.
similar to solvent.
pH and viscosity monitoring and adjustment.
Table 1. Summary of operational advantages and disadvantages of different ink technologies. Own
sources
Interaction Inks-Substrates
Consideration of the substrate to be printed on is of fundamental importance to ink
formulation, particularly when it comes to non-absorbent substrates, such as polyethylene,
where the ink adhesion properties are crucial. The degree of the problem depends on the
formulation of the ink and the surface characteristics of the substrate being printed.
The printability of polyethylene and other plastic surfaces is determined by their molecular
polarity with respect to that of the ink vehicle. The total surface free energy of a non-polar or
low polarity substrate is low and consists mainly of the dispersive component. In order to
increase the polarity of these surfaces and make them receptive to the more polar vehicle
component of water-based inks, they require surface treatment.
Among the methods used in industry to alter the surface energy of a printing substrate, corona
discharge treatment in air is one of the most widely used methods. Ideally, corona treatment
should be carried out in-line or shortly before printing. The total surface free energy increases
and improved adhesion and wetting properties that are vital to ensure satisfactory printability
are achieved. In addition, corona treatment can crosslink surface regions and increase the film
cohesive strength.
Corona treatment can also lead to physical changes in the polymer surface in forms of
micropits and surface roughness. Caution should be used in corona treating in order not to
over treat the film as this can damage or distort the surface of the substrate. Another effect of
corona treatment is that surface contaminants, such as plasticizers that have leached to the
surface, can be removed.
As a result of corona treatment, the drying speed may be improved. When the corona
treatment of a film is high, the rate of flow-out can be more rapid, leading to a thinner layer of
ink-film, which can dry faster. Corona treatment, however, is reversible. The increase in
surface energy that is induced on the plastic surface begins to decay immediately after the
treatment. This decay is most rapid in the beginning and levels out as time passes depending
on start level, type of polymer surface, and humidity.
Different ink/film combinations were printed and assessed in Action A.1 of ECOFLEXOBAG. The
results showed that:
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PLA and starch based films could achieve similar print quality in terms of tone
reproduction and dot shape with solvent based inks. But when printed with water
based inks PLA and starch showed a poor behaviour in dot shape and in solid
reproduction. In fact, the water based inks performed worse than the solvent inks in
solid reproduction, this is due to the high surface tension of water when compared
with solvents and could be improved by adding surfactants to the ink or improving the
surface treatment of the films.
All tested film showed similar color response with the different inks, and the solvent
and water based inks had a very similar colorimetric response.
All the samples performed well in the rub test, not founding any combination giving
especially bad results, so the rub resistance was correct in all the samples.
In the light fastness tests al the inks behave the same way no matter what substrate
they were printed on, so the conclusion is that the substrate doesn’t affect the light
fastness. In general all the inks performed well but the water based yellows.
In folding resistance all the samples performed well and increasing resistance there
were just two combinations that gave results under the acceptable: LDPE and HDPE
with water based inks.
Further information about sustainability of printing substrates is available in Deliverable B.1.1
“Procedure for design sustainable Commercial Bag” (4.3.1.2 Selection of low impact materials).
Further information about substrates properties related to printing is available in Annex.
“Flexography Inks properties”
3.4 Plastic Bags BATs
The term “Best Available Techniques” (BATs) is defined in Article 3 of the Directive 2010/75/EU
as ‘the most effective and advanced stage in the development of activities and their methods
of operation which indicate the practical suitability of particular techniques for providing in
principle the basis for emission limit values designed to prevent and, where that is not
practicable, generally to reduce emissions and the impact on the environment as a whole.’
Article 2 goes on to clarify further this definition as follows:
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‘techniques’ includes both the technology used and the way in which the installation is
designed, built, maintained, operated and decommissioned;
‘available’ techniques are those developed on a scale which allows implementation in
the relevant industrial sector, under economically and technically viable conditions,
taking into consideration the costs and advantages, whether or not the techniques are
used or produced inside the Member State in question, as long as they are reasonably
accessible to the operator;
‘best’ means most effective in achieving a high general level of protection of the
environment as a whole.
The BAT (Best Available Techniques) Referent Document (BREF) “Surface Treatment Using
Organic Solvents (STS) determine the Best Available Techniques for “Flexible Package Printing
– Flexography and Gravure (page 126/723) for reducing the VOCs emissions, which are
generically applicable to the production of printed Plastic Commercial Bags.
However, after evaluating the specific technical and economical context of the Plastic
Commercial Bags and the updated state of the art, the applicability of these BATs to the
production of Plastic Commercial Bags is reduced and focused to some concrete techniques.
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Other techniques can be considered as Emergent Techniques and must be communicated to
the Plastic Bags Manufacturers in order to boost their implementation within the Industry.
3.4.1. Water Based Inks
In flexography, press-ready inks contain about 80 % solvents. These are always mixtures of
several solvents, e.g. ethanol and ethyl acetate. Substitution with water-based inks can result
in significant reductions in solvent emissions, particularly of fugitive emissions.
However, most flexography printing plants are equipped with waste gas abatement systems
and in that situation the achievable reduction in solvent emission is clearly smaller. Where
waste gases are efficiently treated and excessive fugitive emissions are avoided, little further
gain is made by switching to water-based inks
Water-based inks may require more energy for drying, however, the total plant energy
consumption will be reduced because no waste gas treatment system is required.
Where water-based products (inks, varnishes, etc.) are applied on existing presses, the drier
systems are often found to lack capacity. This reduces the applicability on existing presses.
Changing from solvent-based to water-based inks could involve substantial changeover costs.
For new presses applying water-based inks, the investment is approximately the same as for
presses for solvent-based inks. In the case of retrofit, substantial investment may be needed if
the drier capacities need to be enlarged. 4
Since water-based inks are more highly pigmented, less is needed and the operational cost per
m² of printed material will generally be somewhat lower than the cost of solvent-based inks.
Where, in the case of water-based inks, printing speed and flexibility can be maintained and
the investment in abatement equipment and other solvent related costs can be avoided,
substantial savings may result.
3.4.2 Water Processable Plates
Technology now exists so that flexographic printing plates can be manufactured using entirely
VOC free processes. The plate is produced in the same manner as the solvent processed digital
plates however, following front exposure, the uncured photopolymer material is washed out
using water (figure 2). The main advantages are the elimination of VOCs in the production
process with the additional benefit of water filtration recycling. The only waste is the uncured
polymer. The cured plate material absorbs little of the water in comparison to the solvent
process plates and therefore there is a further saving in the reduced drying requirements and
hence faster production speed
4
IPPC Bureau. European Commission. 2008. Reference Document on Best Available Techniques on
Surface Treatment using Organic Solvents
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Figure 2. Flexographic plate making process used by Cosmolight water wash plate
The plate technology is compatible with UV, solvent and water based inks and has a special
plate surface that prevents ink build up in fine detail areas; allowing for longer run lengths
between cleaning/plate replacement. Fine detail is often not required in bag printing
applications, however it has been observed that should the plate require cleaning (e.g. for
removing debris), the surface can be removed potentially introducing a colour difference
through the run.
3.4.3 Cleaning Materials
When using Water Based Inks, further solvent reduction is achieved through the use of waterbased cleaners however in practice solvent cleaners are often used, especially where inks have
dried. As water has a lower volatility than solvents used in inks, the drier power requirements
are higher which can limit production speed for existing installations.
Alternatives to conventional solvent-based cleaning solutions are increasingly available. These
offer a more environmentally friendly solution that also is safer for operators. Water-based
and biodegradable cleaning agents have been specifically designed to clean solvent or UV inks.
However in some cases the cleaners take more time and effort to achieve the same level of
cleanliness and are more expensive than cleaning solvents.
3.4.4 Management and Operational Techniques
Overlooked techniques identified have mainly involved management or operational processes
for optimizing workplace efficiency such as the principles of lean sigma from the automotive
industry, maintenance and stock control. Overlooked techniques for the energy reduction has
identified centralized systems, using minimal dryer requirements, weight reduction and
switching off when not in use as potential environmental improvements. Waste reduction can
be implemented using automated setup equipment and finding commercial opportunities for
waste such as the sale of waste polypropylene to drain pipe manufactures. Further benefits
can be found by using standard layouts, colour management, standard operating procedures
and ink tank volume reduction.
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4 PRINTING PROCEDURES; STEP BY STEP
For a summary of the Sustainable Printing Procedure, only including short instructions, go to
Annex. Summary of Sustainable Printing Procedure
4.1 Pre Conditions
Figure 3: Scheme of Preconditions actions
4.1.1 To ensure regular internal communication
Important conditions for successful Sustainable Printing of Commercial Bags are a sufficient
common basis of support and good internal communications within the company. This applies
for both the employer and for the printers. There are also the chief operators/foremen who
are responsible to the management and must lead by example. Taking everything into
account, there are quite some layers within the organization that must support the
introduction of new materials and procedures within the company. Ensure regular
communication about the issues related to Sustainable Printing of Commercial Bags and make
use of the existing means of communication when doing so. It is possible to raise Sustainable
Printing as a recurring point in the work meetings; it may also be good to dedicate newsletters
to the topic. To further organize the basis of support within your company ECOFLEXOBAG
advises printers to make clear agreements about the work and make a clear division of tasks.
This will contribute to a successful introduction of Sustainable Printing measures. This is
because clear definition of the responsibilities on this theme within the company prevents
unneeded misunderstandings
 Tools; No needed
 Mandatory; Yes
 Investment; No
4.1.2 Working on external communication and support
While Sustainable Printing is an internal matter it may be opportune to inform the most
important clients about the project of improving the environmental performance of the
products. On the one hand the printers show their company’s involvement with Corporate
Social Responsibility, on the other hand the may be able to arrange some leeway regarding the
delivery dates or quality of printed product. Suppose for instance that a serious problem
occurs during the introduction of new materials and/or procedures. This may cause friction
DELIVERABLE B.2.1 SUSTAINABLE PRINTING PROCEDURE
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with the client. It is therefore wise to change this threat into an opportunity by informing the
clients about the Sustainable Printing policy in advance. In addition it is important that printers
arrange support from external experts during the start up of using new materials and/or
procedures. When technical matters are concerned suppliers must be primary contact. For
more generalist concerns it may be best to approach a consultant, independent from supplier
brands and may therefore offer a more objective advice.
 Tools; No needed
 Mandatory; No
 Investment; No
4.1.3 Implementing a quality control system
The clue to get a high printing quality when changing from solvent based inks to a water based
inks with new sustainable substrates is to implement a reliable printing control parameters
system supported by the appropriated equipment to control the colourimetry, densitometry
and dot gain and the rest of printing quality parameters. This will allow the company to
establish, achieve and maintain an objective quality target, by means of the densitometry and
dot gain control.It is essential to have the appropriate equipment with the correct
configuration. A reliable printing parameters control will need a spectrodensitometer. Density
and dot gain values should be measured using polarization filter and L*a*b* color values must
not use any filter. The other measurement conditions will follow ISO 12647-6 specification:








Device geometry: 45º/0º or 0º/45º
Bandwidth response: Status E
Backing: black, matt, L<5
Illuminant: D50
Observator: 2º
Tools; No needed
Mandatory; Depending on customer requirements
Investment; Yes
4.1.4 Checks on the harmfulness / hazardous nature of materials and additives
Even though this should not be a topic that needs mentioning anymore it remains prudent to
use the safety information sheets to check whether there are harmful components in the
materials and additives used in the printing processes, paying special attention to
environmental and Health & Safety cross effects.
 Tools; No needed
 Mandatory; Yes
 Investment; No
4.1.5 Technical knowledge update
This topic may appear strange within the subject of creating conditions. The execution of
preparatory investigations does however have its place within step 1. This is because it is
important to obtain sufficient knowledge about some important parameters of the printing
process, especially those related with the bases for the behavior of water based inks.
 Tools; No needed
 Mandatory; This document, including Annexes is a good source of this technical
information
 Investment; No
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4.2 Graphic Design
Figure 4: Scheme of Design actions
4.2.1 Properly specify the digital file for printing
Select and manage correct formats
Avoid converting from one file type to another. Two types of file format are recommended for
transfer of information by the International Standards Organisation (ISO)


The publicly available Adobe Portable Document Format (PDF) is recommended for the
transfer of object based files where objects may be either raster or vector data
structures [1]. The use of PDF (either PDF/X-1 or PDF/X-1a) is intended to provide a
complete single file for the transfer of CMYK data and must contain all information
needed for further processing.
For the interchange of raster and monochrome data the Adobe Tag image file format
for image technology (TIFF/IT), version 6.0 file format is recommended
There will be occasions where the PDF or TIFF file format may not be appropriate, the prepress
supplier is often best placed to advise as they will have the programs and knowledge to make
file conversions. Taking this into account, file format should still be agreed by all stakeholders
for file creation, exchange and archiving.
Use correct fonts
Avoid fonts that have been stroked or swelled. Print failures can occur in due to filling in of
font elements such as counters and apertures. It is also important to avoid narrow text
elements which can occur if a serif is applied to a font. Fonts that are too small will also suffer
from fill in of counters and bleed into adjacent characters. Suggested change: Achievable font
will be affected by ink, substrate, press etc. therefore minimum font size should be
recommended by the printer following press fingerprinting. The same is also true of minimum
size of line however as a guide fonts below 8pt in positive and 10pt in reverse should not be
used with minimum line width of 0.18 mm in positive and 0.38 mm in reverse .
Use trapping
Trapping should be used to prevent substrate show through by spreading the lighter of the
two colours under the darker of the two.
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An increase in trapping may therefore be appropriate, especially while experience is gained in
using water based inks with sustainable substrates. Trapping values of 0.190mm for wide web
printers and 0.13mm for narrow web printers should be sufficient
Determination of appropriated Total Ink Coverage
Total ink coverage of 300-340% would be typical for flexographic print using water based ink
onto sustainable substrate. Advantages can be gained by reducing total ink coverage where
possible by reducing ink usage and reducing dryer power (or increasing productivity).
Reduction of ink coverage is achieved using under colour removal (UCR) and grey component
replacement (GCR) techniques. Both UCR and GCR reduce ink usage by replacing CMY with
black ink. In the case of UCR equal amounts of CMY are removed and replaced with black to
darken shadow areas, for GCR single colours are replaced where they are being used to darken
tones
 Tools; Job Option could be used. ECOFLEXOBAG will developed a suitable Job Option in
next stages of the project
 Mandatory; NO, if the established workflow accept other formats and if any problem
occurs during inks substitution
 Investment; No
4.2.2 Use process and mechanical control elements
Control elements are important for successfully achieving the print result. Furthermore, the
correct use of control elements can improve environmental performance through reduced
wastage and set up times. Control elements requirements will depend upon the type of image
to be printed i.e. if the artwork is to be line or process work.
Registration marks will be universally required. Registration marks can be simple cross hairs
placed in the same position on each separation (print colour). Aligning these cross hairs
ensures that each print unit is correctly positioned relative to one another.
Line work (or spot colour) makes up a large percentage of bag printing with typically only one
or two solid colours printed. In this case, control elements can be made up of a solid patch for
each colour that can be measured for colour reproduction.
Process work is more complicated as the combination of different colour percentages is used
to reproduce the required colour. It is therefore more important to include additional control
elements for trapping, slur and grey balance. The process colour control marks should include
a range of tonal values to include the lowest and highest tonal area in the print as well as
midtone coverage for determination of tone gain values.
Solid colour patches should be included for each colour printed so that they can be measured
to determine correct density and colour values. In addition the inclusion of tone scales allows
the calculation of tone gain by measuring density of the solid and tonal patches. Measurement
of tone gain ensures set-up and through run control maintains printing conditions to those
achieved during fingerprinting.
Grey balance control patches compare combination of Cyan, Magenta and Yellow to the
equivalent greyscale (black only) print. These targets can often provide the first indication of
changes in on press performance when colour changes occur between the CMY and equivalent
grey scale patch.
Trapping targets are included to ensure smooth lay down of one ink layer over the other which
may be affected by ink drying, metering or chemistry.
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Slur targets can take several forms. They are used to determine correct impression of the
printing plate by visual inspection of the target. In the case of the hexagonal slur target an
hour glass shape will become visible in the target if the plate is over impressed.
Consideration should be given to additional control elements such as head-up arrows, which
when combined with standard operating procedures ensure plates are always mounted in the
correct direction avoiding wastage from individual misaligned prints and ensuring the web is
correctly orientated for further processing.
Further information is available in the Annex “Flexography Quality Parameters”
 Tools; ECOFLEXOBAG Control Elements_FB.2.1 (enclosed). Consider 2/3 control sets
for different printing complexity
 Mandatory; Depending on customer requirements
 Investment; No
4.2.3 Colour Conversion (using ICC Profiles)
When using ICC Profiles a standard profile or a specific profile could be used. In order to make
a specific profile, a test target must be produced on each device to cover the achievable colour
gamut and a conversion profile produced so that the same colour is reproduced on each
device However, different colour management systems can produce slightly different ICC
profiles and different programs using the same ICC profile can produce different results. It is
therefore important to standardize the workflow of the artwork. The International Color
Consortium (ICC) sets out how to conduct this conversion in ISO 15076-1:2010 [4] and
ICC.1:2010 [5] and allows correct colour rendering on different devices including the printing
press
 Tools; See Fingerprint in Press Optimization
 Mandatory; NO, except for specific requeriments
 Investment; No
4.2.4 Checking digital files “Pre-flight”
The digital files should be transferred to a different computer (a less reliable method is to copy
to a different directory on the same computer) with only standard fonts enabled and the file
opened. This will highlight any issues occurring with missing links or fonts that have not been
imbedded in the file. When any highlighted errors have been corrected the file should be sent
to a desktop printer, this is a low quality proof but can highlight issues at an early stage. If
these tests have been passed then the files are clear to be passed on to the next stage of
production. There are also software applications available to conduct pre-flight checks, these
programs will check images are properly embedded, check fonts and image files and confirms
colour profiles are included and correct colour separations can be output. Accompanying the
transferred design files should be a pre-flight report. The report should include the file names,
full resolution and FPO images, template identification, software used, fonts used, colours
used (CMYK and custom) and instructions for effects.
 Tools; Job Option could be used. ECOFLEXOBAG will developed a suitable Job Option in
next stages of the project
 Mandatory; NO, if the established workflow accept other formats and if any problem
occurs during inks substitution
 Investment; No
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4.3 Color Proof
Figure 5 Scheme of Control Proof Procedures
4.3.1 Producing the colour proof
The proof should be produced using the profile from the specific press used for production
through the colour management system.
The colour proof must accurately match the production print. Where possible, it should be
produced on the same substrate as used for production. If this is not possible, a substrate with
the same gloss level and CIE Lab a/b values of ±0.2 should be used.
 Tools; No
 Mandatory; NO, except for specific customers requirements
 Investment; No
4.3.2 Control of Colour Proof
Include proper control elements
The proof must contain the same process control elements which will be used for
measurement of the proof. If the process control elements are positioned outside of the trim
area it is important that they are included in the proof.
The control elements of the proof should be measured as described in ISO13655:2009 so that
the same measurements can be performed by the press operator to enable an exact match.
Preferably measurements of the proof will be documented and accompany the proof for on
press colour matching
Measurement of Color Proof
Ink density measurements can be obtained using a densitometer; these can be used to
measure film weight and calculate tone gain.
The measurement of colour should be measured over a wavelength range of 400nm to 700nm
using standard measurement geometry (0°:45° or 45°:0°) capable of measurements according
to ISO 13655:2009.
As the substrate is unlikely to be totally opaque a substrate backing must be used when
measuring the sample, this can either be a black or white background. If using a black
background it must be spectrally non-selective, diffuse reflecting, opaque and have a reflection
DELIVERABLE B.2.1 SUSTAINABLE PRINTING PROCEDURE
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density of 1,3. A standard white backing shall be opaque (greater than 99), diffuse reflecting
and non-fluorescent. The CIELAB C* shall not be greater than 3 and preferable lower than 3,4
with spectral reflectance values in excess of those in Figure 7.4.
Wavelength (nm)
Spectral Reflectance factor value
400
0,30
410
0,30
420
0,75
450
0,75
460
0,80
670
0,80
680
0,75
700
0,75
NOTE This corresponds to a CIE L* greater than 92
Table2. Spectral reflectance values for colour measuring device.
There are several measurement conditions specified; M0, M1, M2 and M3. Condition M3
concerns the use of a polarising filter to suppress the influence of first surface reflection.
Condition M2 is used to reduce measurement variations due to optical brighteners in the
substrate (usually present in paper substrates) by excluding illumination at wavelengths below
400nm. Condition M0 exists to allow the use of older measurement equipment that utilises the
CIE standard illuminant A however this should only be used when condition M1 is not
available. Condition M1 specifies the use of CIE illuminant D50 as this illuminant is also
specified in ISO 3664 (viewing booth specifications) the use of D50 illuminant will be preferred
in many cases to improve consistency between measurement results and visual assessment.
Correct visualization of the Colour Proof
The use of a viewing booth helps to achieve the requirement for ambient viewing conditions.
To use viewing booth with a D50 standard illuminant with the proof orientated to avoid
specula reflection and surrounded by a neutral border as described in ISO 3664-2009 [8].
Specular reflection must be avoided by positioning the light source, image and observers eyes
to avoid reflection near the normal to the centre of the viewing surface. The neutral boarder
must be made up of a diffuse reflecting surface with a CIELAB chroma value of 2 or less relative
to a perfect reflecting diffuser at the viewing surface. Extraneous light from other light sources
or reflections from surfaces or near bright objects should be hidden from view and prevented
from illuminating the proof.
For critical comparison of the proof to print condition P1 should be used:






D50 illuminant should illuminate the centre of the viewing surface at 2000 ±500lx with
1m2 not less than 75% of that value.
The surround and backing shall be neutral and matt with a luminous reflectance
between 10% and 60%.
The surround should extend beyond the proof by at least one third of the dimensions
of the proof and the backing, which shall not extend beyond the proof, can be either
white or black.
The backing should be the same as used for measurement of the proof.
For evaluation of a proof on its own a better appraisal of tone reproduction is achieved
using condition P2 which is the same as P1 except that illuminance shall be 500±125lx.
Tools; Control Elements, see Graphic Design
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

Mandatory; NO, except for specific customers requirements
Investment; Optical device and Viewing booth
4.4 Printing Form
Figure 6. Scheme of Control Proof Procedures
4.4.1 To determine proper specifications
Relief of the exposed elements
The optimal relief depth is dependent on the plate thickness, line ruling and hardness and
should be selected in consultation with the pre-press or plate supplier however should be in
the range as shown in table 3.
Plate thickness (mm)
Relief -Sheet plates (mm)
Relief - Sleeves (mm)
0,762
0,584
0,508
1,14-2,72
0,457-0,559
0,457-0,559
2,85
0,508-0,635
0,508-0,635
3,18
0,508-0.635
N/A
3,94-4,70
0,762-0,889
N/A
Table 3 Recommended plate relief depths.
Angles for process colour printing
Screen angles should be 30 degrees apart for C,M,K with yellow 15 degree between cyan and
black. No colour should have the same angle as the anilox. Commonly used screen angles for
process colours are 7.5, 52.5, 22.5 and 82.5 or 82.5, 37.5, 7.5 and 67.5. for Y, M, C, K print
sequence.
Screening, according the image to be printed
For line and high density solid work a course anilox will be used and therefore a course plate
screen ruling will be used.
For process work a higher plate screening will be used in the range of 110-175lpi (43-69lpcm)
as long as the anilox ruling is at least 4x that of the plate.
Dot shape
A round dot shape should be used, this shape is optimum for reduction of dot spreading in
highlight areas and avoids fill in of the shadows.
Printing form hardness
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To determine proper printing form hardness, selected in combination with the mounting tape
and consideration of the image to be printed
Solid prints should use soft plate material, this allows the plate to take up the deformation in
the printing nip evening out the printing and reducing print defects. For accurate highlight and
halftone reproduction a hard plate material should be used (with soft tape) this allows a
greater amount of deformation by the mounting tape in the printing nip. Lower deformation of
the plate results in lower tone gain due to expansion and barrelling of the plate dots in the
printing nip.
Where solids and halftones are combined on the same plate the hardness of the plate material
must be selected dependent upon the importance of achieving good solid or good highlight
reproduction. Alternatively a combination of medium hardness plate and tape may be used.
Plate surface tension
The surface tension of water-based inks is higher than that of solvent based inks therefore it
may be necessary to change plate materials to higher surface energy alternative. Many plate
materials however are suitable for printing of solvent, water and UV curing inks therefore the
plate manufacturer should be consulted for compatibility with selected inks.



Tools; Ecoflexobag Specification Forms_FB.2.2
Mandatory; Yes
Investment; No
4.4.2 Control Environmental Conditions of Printing Form
To determine and keep constant environmental conditions for the production and storage of
flexographic printing plates
Temperatures should be kept below 30°C and plate material, particularly photopolymer
protected from white light. This can be conducted by wrapping sleeves and storing sheets in
envelopes (with paper or foam between plates). Plates should also be kept away from sources
of ozone such as corona units.



Tools; No
Mandatory; No
Investment; No
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4.5 Anilox
Figure 7. Scheme of Anilox Procedures
Water based inks are generally more highly pigmented than solvent based so the anilox
volume required is usually lower. Water based inks are also reported to be more likely to dry in
to anilox cells causing loss of volume during a press run and cell plugging causing long term
drift in anilox volume
4.5.1 To select optimum anilox specifications
Anilox geometry
The optimum depth to opening ratio for ink release should be in the region of 23-33%. This
relationship between the depth and opening of the cell generally gives the optimum release of
ink from the anilox to the plate in each pass and the more open cell structure (compared to
deeper cells) allows for easier cleaning of solvent based inks.
Water-based inks however have a greater tendency to dry in the anilox cells, with poor
rewetting making them difficult to clean. It therefore may be beneficial to specify a slightly
higher volume anilox roll with a higher depth to opening ratio of up to 50%, with the lower
release from the anilox compensating for the extra volume.
The larger volume of ink remaining in the cell will take longer to dry in, giving more flexibility
to the press operators and more time during clean up to get cleaning agents onto the roll. This
should be considered in the context of the cleaning system used on press, for example,
automatic wash up systems may be able to adequately clean optimum depth to opening rolls
and additional depth will be detrimental to the clean up.
Anilox screening
The anilox screening should always be at least 4x that of the plate. This avoids dot dipping
where the highlight dots enter the cell and therefore carry large volumes to the substrate
vastly enlarging the dots.
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Anilox ruling also depends upon volume required but should be as high as possible with
respect to the volume to be carried and effectiveness of cleaning for the ink type. Given the
tendency for water based inks to dry in to the anilox cell screening should be kept as close to
4x plate screen ruling (or maximum anticipated plate ruling) as practically possible.
The screen angle of the anilox is determined in relation to the circumference of the roll. The
simplest screen angle is 90°, where a line of cells is engraved around the circumference; the
next line of cells is engraved next to the first. Other screen angles are created by the offset
between adjacent rows of cells, for example a 45° screen angle is created with a half cell offset
between rows. The screen angle in combination with the cell shape affects the packing of cells,
a hexagonal cell with 60° angle is reported to give optimum packing and is usually the
optimum screen angle.
Anilox cell shape
The complex patterns can be continuous patterns of grooves around the circumference of the
roll [14] however the most commonly used cell shape is the hexagonal cell. Combined with a
60 degree screen angle the hexagonal cell optimises cell packing, minimising land area (cell
wall area) between cells.

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
Tools; Ecoflexobag Specification Forms_FB.2.2
Mandatory; No, if any problem occurs during inks substitution
Investment; No
7.5.2 To control the environmental conditions of the anilox
The use of ceramic anilox rolls does not require any specific environmental conditions.
However, extremes of temperature changes and excess humidity that may damage gears or
bearings should be avoided.



Tools; No
Mandatory; No
Investment; No
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4.6 Plate Mounting
Figure 8. Scheme of Control Proof Procedures
4.6.1 To control the critical features of the adhesive tape
The most important factor that can be selected by the operator is the compressibility of the
tape. There may be no compression in the tape selected but it is more likely that the tape will
be selected from a range of hard to soft.
Selection is dependent on the coverage of each individual plate and is not necessarily the same
for each plate of a print job. Where the majority of the print is solid, a hard tape will be used,
this allows the engagement in the nip to be taken up by deformation of the plate giving good
contact and therefore even transfer of ink to the substrate. Where there are significant
highlights on the plate, a soft tape will be chosen, the deformation is therefore taken up by the
tape preventing excessive spreading or dot collapse. Where solids and highlights are combined
on the same plate a judgment must be made on the hardness of the tape to best
accommodate the most important features.



Tools; Ecoflexobag Specification Forms_FB.2.2
Mandatory; Yes
Investment; No
7.6.2 To control the critical features of sleeves
It is important to select a resin composition that is not susceptible to water ingress as this
weakens the sleeve when using water based inks



Tools; Ecoflexobag Specification Forms_FB.2.2
Mandatory; Yes
Investment; No
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4.7 Ink Formulation
Figure 8. Scheme of Ink Formulation Procedures
4.7.1 Control of Raw Materials
To control the critical features of the materials for ink making, including water.Raw materials
for ink making (including water) can vary from supplier to supplier and between batches. It is
therefore important that materials are supplied with agreed certificates of conformance. In
house checks should also be conducted to prevent unsuitable materials being used in the
formulation, resulting in waste of all materials used. Understanding of the supply can also be a
benefit. For example, in some regions the water supply may come from multiple sources that
can be switched on a seasonal or daily basis. Different supplies will contain different minerals
and therefore affect the additive requirements of the ink



Tools; No
Mandatory; No
Investment; No
4.7.2 To specify the critical formulation parameter
To control the critical formulation parameters of the inks for consistently replicating the
colour, viscosity, specific gravity, pH and solid content.
Ink viscosity: The most accurate method for determining ink viscosity is to use a rotational
viscometer however most viscosity control is conducted using dip cups. Standardised cups
such as Zahn or shell cups are filled with ink; an aperture in the bottom allows ink to flow out
and the time taken for the cup to empty recorded. Viscosity should be controlled to within ±
3seconds.
Specific gravity: The specific gravity is related to the solid content of the ink and therefore if
blended correctly should not alter from batch to batch.
pH: Water based inks are typically alkaline with pH between 7.5 and 9.5 depending upon the
specific formulation. The pH should be measured using a pH meter at least every 30min during
the run.
Solid content: solid content as with specific gravity it should not alter from batch to batch.
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Colour: It should be measured at the predefined viscosity by creation of a test sample using a
mechanical drawdown test. The formulation can initially be tested by visual comparison to a
standard swatch. When a visual match is achieved a spectrophotometer is then used to match
the colour to digitally held colour standard measurements within a tolerance of ±ΔE 2.



Tools; Ecoflexobag Specification Forms_FB.2.2
Mandatory; No
Investment; No
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4.8 Press Optimization
Figure 9. Scheme of Press Optimization Procedures
4.8.1 Variation of Print Process Parameters
In a press optimization fingerprinting trial the print process parameters are varied in order to
find the optimum output and it´s essential when changing from solvent to water-based inks.
The optimization trial will be conducted using the water based ink and sustainable substrate
combinations to be used in the production run.
The most important factor to include in the fingerprinting trial is the anilox, a banded anilox
roll should be used to determine the optimal volume, cell count and geometry. Other factors
to consider are mounting tape, plate material and dryer settings. The same image is printed for
each anilox band and for process colours will include tonal scales, positive and reverse type
and lines and a solid patch however if a full fingerprinting test form can be included the
optimum samples can be used to create the ICC profile.
Water based inks and selected substrate will be used for printing a specific optimization test.
The next print process parameters will be varied in order to find the optimum output in terms
of:








Inks pH
Inks Temperature
Inks Viscosity
Production Speed
Dryer Settings
Corona Treatment (Critical for Water Based Inks)
Anilox Volume (A Banded Anilox should be used)
Tools; Optimization Test_ FB.2.3 + Banded Anilox Test__ FB.2.4 Ecoflexobag
Specification Forms_FB.2.2
 Mandatory; Yes
 Investment; Banded Anilox. If this Anilox is not available, different trials should be
made with conventional Anilox with different volumes.
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4.8.2 Determination of Optimum conditions
Optimum conditions will be determined as those that produce best printing quality defined as:







Lower tone gain
Smallest text reproduced
Minimum line widths reproduced
Visual Quality of Images
Visual homogeneity of solid tones
Register
Slur
Print Process Parameters delivering the optimum conditions will be writen down in a
Specification Form, including the resulting Total Ink Coverage and Density.
 Tools; Optimization Test_ FB.2.3 + Ecoflexobag Specification Forms_FB.2.2
 Mandatory; Yes
 Investment; No
4.8.3 Producing the ICC Profile. Fingerprint
Assuming the optimization trials have been conducted the following procedure should be used
for producing the ICC profile:
Design of fingerprinting test pattern; An IT8.7/4 characterization target should be used. The
IT8.7/4 test pattern is a combination of 1617 test patches incorporating solid colour patches,
process colour tonal patches, grey balance and near neutral patches, RGB overprint and CMYK
combination patches.
Printing and sample collection; The test pattern should be printed using the process
parameters determined during press optimization. The trial should run for at least 30min,
longer if long runs are expected and the press stabilized before samples collected.
Sample Measurement; Samples should be measured using a spectrodensitometer. An
automated measurement table is preferable given the large amount of measurements
required. 6 samples should be measured and the results averaged.
ICC Profile; The data is then entered into ICC profile creating software. This might be part of
the graphics application or a standalone programme. Often profile creating software will be
packaged with the sample measurement device
 Tools; IT8.7/4 characterisation target included in Optimization Test_ FB.2.3
 Mandatory; No, except for specific requeriments
 Investment; No
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4.9 Printing
Figure 10. Scheme of Printing Procedures
4.9.1 Machine Set Up
Machine adjustment with the settings defined in the Press Optimization
 Tools; No
 Mandatory; Yes
 Investment; No
4.9.2 Production of OK print
The printing result will be compared with the reference established by the company within the
predefined tolerances, which could be different depending on the company and products
(color proof, previous work, validation of customer…). Definition of tolerances is highly
dependent upon customer expectations; short run spot colour jobs may have loose tolerances
and to use tight tolerances would only increase wastage that could be saleable copy. For high
quality longer runs it is likely that tighter tolerance values will be used with measurement and
control of more quality control features. The validation of the OK Print could be done with 2
options depending on the usual procedures of the company:
1. Visual
2. Measurements (within tolerance, density, slur, dot gain and ΔE colour difference to proof
must all be within tolerance values for OK print to be achieved)
The press must be run up to speed and print units thrown on and brought into register. A
sample is then taken and density measurements taken, if density values are not within
tolerance changes should be made and the press run. This continues until all controls are
within tolerance, density, slur, dot gain and ΔE colour difference to proof must all be within
tolerance values for OK print to be achieved.
Slur patches and tonal patches are used to detect excessive impression. Slur patches provide a
visual assessment however tonal patches are measured using a densitometer.
The density is measured for solid and halftone patches and the coverage calculated using the
Murray Davies equation (equation 2). Tone gain is the intended coverage subtracted from the
measured coverage. In most cases reduction of the tone gain is the aim but this should not be
done at the expense of solid laydown.
Equation 2 % coverage=100×(1-〖10〗^(-Density of halftone)))/(1-〖10〗^(-(Density of solid))
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The solid density is measured using a densitometer (or spectrophotometer) and can be
measured for process and spot colours, typical tolerance values will be target ±0.05. Additional
control is achieved by measuring ΔE colour difference; this provides a numerical value to
define the difference in colour between proof and print. There are different colour difference
formulae; ΔE2000 is the most accurate method for calculating colour difference as it accounts
for differences in colour perception a different hue angles. ΔE2000 however requires relatively
complex calculation therefore ΔE1976 may be preferred. ΔE76 is calculated by measuring
CIELab values using a spectrophotometer and entering them into equation 3, tolerances of ≤5
are generally acceptable.
Equation 3 ΔE=√(〖(L1-L2)〗^2+〖(a1-a2)〗^2+〖(b1-b2)〗^2 )
Machine adjustment with the settings defined in the Press Optimization
 Tools; Optimization Test_ FB.2.3
 Mandatory; Yes
 Investment; No
4.9.3 Control of printing production
Control the anilox
The anilox should be fully clean when mounted on press. When using water based inks, drying
in is a common problem therefore once ink is applied the anilox should constantly rotate in
wet ink until wash down
 Tools; No
 Mandatory; Yes
 Investment; No
Control the formulated ink
To control the parameters of the on press inks for consistently replicating the colour, viscosity,
specific gravity, pH and solid content. Ideally an automated dosing system will be used to
maintain the ink during the print run maintaining viscosity and pH within acceptable limits.
Alternatively viscosity and pH measurements can be conducted at 30 min intervals with
necessary adjustments made by addition of small quantities of additives.
 Tools; No
 Mandatory; Yes, at least measurements can be conducted at 30 min intervals
 Investment; No
Control of production run elements
The primary control is in the registration marks these must always be kept within tolerance
this will normally be achieved with on press camera systems. The optimum method for
measuring other control elements is to use on press automated 100% inspection systems that
will alert the press operator to deviations. Alternatively samples should be taken regularly and
compared to proof, measurements taken of control elements and maintained within tolerance
to the proof.
 Tools; ECOFLEXOBAG Control Elements_FB.2.1
 Mandatory; Yes
 Investment; No
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4.10 Resource Efficiency Management
Term “resource efficiency” is an umbrella term for efficient use of (natural) resources entering
the production process. It refers namely to raw materials, other materials (including
auxiliaries), fuels, water and energy. However, from a narrower perspective, “resources”
include only primary resources, i.e. excluding energy; then terms “resource efficiency” and
“energy efficiency” are used separately.
The next identifies basic measures that enterprises (in particular SMEs) can implement in their
production processes in order to increase resource efficiency and benefit financially.
The main emphasis is put on



waste management, (In the context of this document, “waste” includes primarily solid
waste and liquid waste. It does not include releases to water and air emissions)
energy efficiency,
water efficiency.
4.10.1 Waste management
Many organisations underestimate how much waste costs them. The true cost of waste isn’t
limited to the charges for disposal. It also includes wasted raw materials, energy and labour –
which can be between 5 and 20 times more than the cost of disposal.
Figure 1 – Distribution of waste cost
There are many benefits associated with preventing waste and improving resource efficiency,
including:




cost savings from reduced raw material and waste disposal costs (typically over 1 % of
turnover can be saved;
improved process performance;
improved environmental performance;
increased competitiveness.
Prevention is always better and cheaper than treatment; therefore all organisations should
aim to prevent waste from the outset wherever possible. In cases when it is not possible,
companies should, according to the waste hierarchy, consider re-using, recycling or recovering
other value (e.g. energy). However, there will usually still be waste that companies will have to
dispose.
In order to achieve the highest benefits possible, it is advisable to address the issue of resource
efficiency in a systematic way and/or incorporate it into company’s (environmental)
management system. However, there are a number of tips that can be considered by a
company to start with (regardless a sector they operate):
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Figure 5– The waste hierarchy (source: [2])




Measurement: If the company does not measure its waste, it cannot be managed as
effectively as it could be. Measurement helps company to make waste cost better
visible. Particular waste streams (e.g. paper, plastics, metal etc.) should be measured
separately.
Segregation:Several kinds of waste can become valuable secondary raw material.
Good segregation helps company to ensure that particular waste is free from
contamination and retains as much value as possible. It can also help to save money as
mixed waste treatment can be more expensive. Company shall also ensure that waste
containers and bins are properly marked.
Selection of containers and bins: Waste containers and bins of appropriate size /
capacity can have a significant impact on waste cost. Moreover, having smaller
containers could mean that they could be situated closer to places where waste is
actually created. Sealed and lockable containers can prevent internal staff or third
parties putting contaminating waste into them.
Shredding and compacting:Much of the space in waste containers is air. Reducing the
amount of air, e.g. by shredding or compacting, will maximise the volume of waste
that can fit in containers.
Other issues than can be considered are summarized in Table 4 sorted by company
departments and production process phases for which they are relevant. Moreover, a few
resource efficiency and waste minimization tips for printing companies are given in Table 5.
Department / area
Important issues
Production







Preventing production area to be used as a store
What is on the floor?
Why is material in the waste bin?
Amount of auxiliary materials used
Amount of consumables (e.g. protective equipment, packaging)
used
Elimination of unnecessary temporary storage, process steps and
movements
Employees awareness and engagement
Cleaning up cost



Efficient utilization of storage space / amount of stock
Preventing stock becoming out of date
First in - first out system

Stores
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

and 

Packaging
dispatch
Preventing stock damages
Suppliers providing re-usable or returnable packaging
Do customers require all the packaging that is used?
Re-usable and returnable packaging
Administration



Monitoring of paper use and waste
Clear instructions for paper use
Electronic communication
Outside premises


Necessity of all waste containers and bins
Compacting / flattening waste
Table 4 Waste prevention issues to focus on in certain departments
Special attention should be paid to hazardous waste. For each hazardous material purchased
or used, a company must have a safety data sheet. When such material becomes waste, it
must be treated in a specific way and can be handed over to authorized person only.
Hazardous materials and waste treatment is always more costly, therefore a company should
look for environmentally friendlier alternatives.
Resource / material
Important issues
Substrates5



Solvents


Inks


Check a substrate on arrival and return it to the supplier if
damaged.
Make sure that staff prepares the press properly to avoid wasting
ink andsubstrate.
Computer-controlled, ink-fed systems linked to a scanner can
reduce set-uptimes, and ink and substrate waste.
Solvent loss through evaporation can be minimised by ensuring
that:
- containers are not left uncovered;
- containers are of sound construction;
- chemicals are stored away from sources ofheat.
Reclamation of solvents from the printing process is possible by
using acondensation plant.
Make sure your inks are stored in the correctcontainers and areas.
Ensure that employeesare well trained in the correct ink
procedures in order to save time, ink, and cleaningand disposal
costs.


Computer-controlled, ink-fed systems linked to a scanner can
reduce set-uptimes, and ink and substrate waste.
Sort jobs to run from light to dark ink, toreduce downtime through
press cleaning.
Table 5 – Resource efficiency issues in printing industry
5
It is estimated that the average substrate waste is 17 %, ranging from 7 % to 33 %.
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4.10.2 Energy efficiency
The printing industry consists of a wide range of activities comprising a variety of processes,
very often specific in terms of their purpose.
An average percentage distribution of energy consumption is shown in the pie chart below:
Figure 6 – The waste hierarchy (source: own, on the basis of [4])
The chart shows that the technology and heating, and also ensuring indoor environment
conditions account for the greatest energy consumption.
There is a potential for energy savings and secondary energy sources utilization in various
fields within the printing industry. The greatest energy savings often rather than from direct
effort to reduce energy consumption result from other objectives implementation as for
instance production quality improving and production costs reduction. Many investments in
non-energy oriented measures bring energy savings as a secondary effect.
The most common kinds of energy saving organizational and investment measures with the
greatest potential for savings can be categorized as follows:

Organizational measures and energy management (organizational measures, control
and monitoring systems installation or improvement, load control system, energy
management system, etc.)

Improving of heat generation and distribution energy efficiency (efficient condensing
boilers, boilers with a high efficiency, installation of economizers, heat distribution
systems insulation, leak repairs, etc.)

Reduction of heat losses in buildings

Improving of refrigeration, air-conditioning and compressed air systems energy
efficiency

Energy efficient lighting systems and high efficiency drives (energy efficient motors –
EEM (with frequency converters), control of electric drives, etc.)
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
Waste heat recovery (effective use of waste heat from technologies)

Energy efficient measures in technological processes - basic technological
modifications, production technology restoration, equipment configuration changes,
decentralization, technological processes optimization, materials recycling, etc.
Above mentioned kinds of measures involve particular sets of no-cost and investment (lowand high-cost) measures specific for each enterprise.
The replacement of a production technology for a modern and efficient one is carried out
above all on the grounds of modernization, extending or introducing a new production to
enterprises. It is a long-term process which causes the savings potential to increase gradually.
The overall technical and economic potential for energy savings in the printing industry was
analyzed and estimated in many studies and analyses. The estimated energy potential
amounts to 30 % (in the Czech Republic). [3]
Organizational measures and energy management
Besides a formalized system of energy management implementation, the organizational
measures involve a lot of specific energy saving measures above all from the category of nocost and low cost measures such as the following ones:





Reduction of no-load running
Regular maintenance, revision and adjustment of equipment and technological
processes
Reduction of uncontrolled ventilation in buildings
Improvement of energy users behaviour
Setting correct contractual relationships with energy suppliers, correct setting of
agreed consumption modes, tariffs,6 etc.
A higher benefit can be reached by involving organizational and investment measures to
formalized and structured energy management system. Energy management is also a part of
IPPC requirements and from this point of view it is the best available technique for improving
energy efficiency and reducing adverse environmental impacts.
The aim of energy management on the level of enterprises is to minimize energy costs from
the short- as well as long- term point of view in providing the quantity of energy for production
in required quality.
Apart from other things, the energy management tools/techniques involve:




Energy audit
Energy assessment
Benchmarking
Monitoring and Targeting (M&T) – an energy management method applied in the
existing enterprise structure, based on data collection and evaluation and improving
measures implementation
The formalized and structured energy management system is focused on several commitments
and processes which can be classified as follows:


6
Policy
Planning and organization
Change of electricity supply company and/or tariffcan save up to 20 %. [1]
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


Monitoring and management
Reporting
Review
It is very difficult to estimate a technical energy saving potential in the field of organizational
measures and energy management. In general, it is higher for light industry and lower for
heavy industry sectors. Based on previous studies and practical findings resulting from energy
audits it is possible to estimate an average potential for the category of organizational
measures for approx. 5 %
Energy management can bring energy savings at relatively low costs by implementing control
systems and energy consumption measurement and invoicing. The energy management
benefit can make additional 5 % of energy savings (in individual cases up to 10 % – 15 %) at low
investment costs of measurement and control techniques introduction, or relevant software,
and formalized procedures implementation.
Organizational measures, implementation of energy management systems and further related
measures belong to the group of no-cost or low cost measures where in majority of cases they
are economically recoverable measures with a payback ranging from several months to a few
years.
Reduction of heat losses in buildings
The main technical measures that can be implemented in the field of reduction of heat losses
in buildings:


Thermal insulation of the building envelope (roof, walls, floor)
Additional thermal insulation or replacement of windows, skylights, doors, gates)
Unfortunately, there are no records or statistics of buildings in industry which makes the
calculation or estimation of energy savings potential for buildings considerably complicated.
An energy savings technical potential estimated on the basis of comparison with other sectors
may be up to 30 % of heat for building heating.
The measures related to buildings fall under the category of high cost measures which in terms
of energy cost savings are long term recoverable (the payback period is more than 10 – 15
years) or irrecoverable ones. Largely it concerns improving the quality of working conditions.
Waste heat utilization
There is a range of technologies and processes in the industry, producing a large amount of
waste heat. Not always a measure for waste heat utilization can be technically implemented. A
significant limitation constitutes also the utilization of waste heat at a given temperature
potential in the place of its origin or vicinity. If it is possible, waste heat can be utilized for
heating or pre-heating the air, water or technological media. As for waste heat of a higher
potential, in some cases it can be utilized for combined heat and power generation (e.g. with
using ORC technology – see below).
The main measures for waste heat utilization in the printing industry are:
1. Utilization of waste heat from compressors: a large number of compressors are used in
compressed air systems, cooling and freezing systems. Waste heat produced in
compressors has a low temperature and can be utilized for heating or preheating domestic
water.
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2. Utilization of waste heat from ventilation systems in buildings: many production halls and
administrative buildings are equipped with forced air ventilation. The outlet air contains a
large amount of low temperature waste heat that can be utilized for preheating incoming
fresh air.
The waste heat utilization measures mostly fall under the category of high cost measures.
Their economic rate of return significantly depends on technical solutions and waste heat
utilization and also on the price of the previous carrier. However, it can be stated that
predominantly these measures are economically recoverable with common payback
period ranging from 3 to 10 years.
Reducing losses in drives
Electric drives constitute a group of energy consumers widely used in all industrial sectors
characterized by constantly high energy potential. In this group of drives, these technical
energy saving measures are available:
1. Optimizing of electric drives capacity: oversizing of electric drives compared to their actual
load is still current in a number of industrial enterprises. Replacing of existing (oversized)
electric drives by highly energy efficient ones together with a proper maintenance may
bring energy savings for drives up to 20 – 30 %. It ranks among mid high costs measures.
2. Introduction of variable speed drives: Electronic control systems for electrical drives that
can adapt to load by changing engine speed may save up to 40 % of electricity used by
drives. The use of variable speed drives with frequency converters is especially suitable for
drives of pumps or fans with variable loads. This measure belongs to the high investment
costs category.
The measures for reducing losses in drives fall under the category of high investment costs.
. The economic rate of return is largely dependent on the performance and on the time
and capacity utilization of the respective equipment, still, in most cases the measures are
economically recoverable.
Shorter payback periods are achieved with the application of frequency converters for
variable speed drives. The payback period ranges between 5 – 10 years (in some cases it is
even round 3 years).
Improving of energy efficiency of energy generation, distribution and consumption
In this category, these measures can be identified:
1. More efficient boilers and fuel switching: this category involves the following energy saving
measures:

A potential for replacing existing boilers for more energy efficient ones
(condensing or low temperature boilers) still exists, although in lesser extent than
in previous years
 Fuel switching – especially the replacement of coal and liquid fuels (heavy fuel oil)
for natural gas
2. Reduction of losses in heat distribution: the measure involves in particular the addition or
replacement of thermal insulation for heat distribution systems. It is a low cost measure
with a short payback period. The specific investment costs are very low and in most cases
it is a measure with a very fast payback within several months or years.
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3. Increasing heat potential: in cases when waste (secondary) heat is not available at the
desired temperature, its utilization requires increasing the thermal potential. To increase
the heat potential, the following steps can be used:

Compression heat pumps, possibly absorption pumps (sometimes also referred to
as heat transformers)
 Organic Rankine Cycle (ORC) – usable also for electricity generation
4. Combined heat and power generation: it is recommended to consider the installation of a
gas engine generating heat for heating and electricity
5. Highly efficient heating systems: this group of measures involves replacement of
conventional heating systems in production halls, typically consisting of a boiler,
distribution system and heaters, or hot air units for highly energy efficient heat sources
such as gas dark radiators (radiant tubes) or infrared heaters (light radiators).
6. Energy savings in technological processes: this group involves a wide range of energy
saving measures. Energy saving measures in technological processes are very specific from
the technological point of view and always have a direct relation to the technological
process in a given production plant. Nearly always they are high cost measures that cannot
be economically evaluated just on the basis of their contribution to energy costs reduction.
Usually it is not the energy costs that gives the primary impetus for their implementation
(although it may be one of the criteria to be taken into account), but requirements related
to the production (an increase or decrease of capacity, increasing the technological
process efficiency, replacement or modification of technologies, meeting environmental
requirements, etc.).
The above mentioned group of measures involves a very diverse range of measures and it
would be very difficult to generalize their economic rate of return. Predominantly they are
high cost measures with the payback period usually exceeding 5 years.
However, in some specific cases, e.g. in the field of reducing distribution heat losses, the
payback of the measures may be rapid in a few months or years.
4.10.3 Water efficiency
Similarly to waste, the true cost of water isn’t limited to bills paid for water supply and disposal
(sewer rate). There are several other costs associated with water use, including for instance
energy costs associated with heating/cooling water, pumps, maintenance cost, etc. Thus, total
cost of water use can be more than three times the amount charged for supply and disposal.
[5]
Moreover, the actual water consumption of a particular manufacturing process may not be
known and is allocated as a proportion of the site’s measured consumption. However, this
approach tends to encourage the incorrect notion that water is a fixed cost in a budget.
Basic information about the use of water in a company and potential improvement can be
obtain from general water mass balance. It is based on comparison of water input and output
during a certain period, which – in general – should be equal. However, the following changes
in water balance have to be considered and added into the calculation:



water removed through drying operations and discharged as vapour directly to
atmosphere;
water removed in the product;
addition of rainwater.
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While a balance of ±10 % is acceptable, a balance of more than 20 % generally indicates an
error or a leak. [5]
The water mass balance can be calculated on a level of the whole company or particular
processes (or even equipment). Information about the amount of water used by each process
helps to identify areas with the greatestopportunities for water savings and efficiency increase,
and so cost savings.
The most typical processes – uses of water – are summarized in Table :
Purpose
Description
Cooling
To remove heat from rotating machinery.
To reduce the temperature of process materials.
To condense vapours.
Processing
Direct contact with raw materials and products to dilute, mix, heat/cool,
and separate raw materials and products.
Cleaning
Used during maintenance activities to clean equipment for:
 hygiene reasons;
 product quality reasons;
 product changeover.
Sanitary
Used for drinking, washing and flushing toilets.
Steam raising
Generating steam for process heating.
Treating
spills/leaks/drips
Abnormal events where water is used to dilute and clean.
Table 7 – Typical uses of water (source: [5])
Identically as waste and energy, water efficiency should be treated in a systematic way in
order for a company to achieve the highest benefits possible; and it is advisable to address this
issue in a company’s (environmental) management system. On the other hand, several general
measures and tips can be considered by a company to start with:

Leaks detection: If there are any unexplained differences in water consumption, it
might indicate possible leaks. When you switch off all the equipment that uses water
(e.g. for weekend or holiday shutdown) but your meter still registers throughput, there
are leaks.

Pipes and taps: Pipes, hoses and taps should be inspected visually and be fixed when
dripping. If the water pressure is too high, some form of flow regulation can be
considered.

Sanitary water:Installation of more efficient taps (e.g. percussion) and automatic
control flushing systems (sensors) can lead to water savings.

Sewerage charges: You can get discount on sewer rate from your water company if not
all your water goes down the drain (e.g. it evaporates).

Hot water: Reduction of water temperature can lower energy costs. Installation of
point-of-use heaters can be considered if washrooms (and other points of use) are
located some distance from the hot water supply. Appropriate pipework insulation
should be provided.
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4.10.4 Horizontal issues
Systematic approach
Previous information provide an overview of important issues and concrete measures that
companies can consider and implement to improve resource efficiency in relation to materials
(waste management), energy and water, and relevant financial savings.
However, in order to achieve higher benefits, companies should address resource efficiency in
a more systematic way. Developing a structured and managed approach can identify additional
opportunities and set actions for continual improvement.
As a first step, commitment from senior management has to be gained, because any important
change will require top-level support. When “green light” from top management is received, a
systematic approach towards resource efficiency can be implemented in four steps:




Assess;
Plan;
Implement;
Review.
Figure 10– Continual improvement approach (source: [2])
Assess



Review of current performance.
Identification of opportunities for resource efficiency, savings and improvements. (It
may involve collecting and analysing existing and new data, survey among staff, etc.).
It will also provide a baseline against which progress can be measured.
Assessment of possible options for improvement.
At the assessment stage, the questions and issues listed in are important to be addressed for
each resource efficiency field.
In this step, it is also important to engage and motivate staff. They can help with identification
of improvements and once particular measure is implemented, their behaviour and operation
practices will be crucial for its success.
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Resource efficiency
field
Questions and issues
Waste






What kind of wastes the company produces?
Where waste is being produced?
How much of (each) waste is produced?
Why waste is produced?
Can waste be prevented / re-used / recycled?
Have any resource efficiency measures already been implemented?
Energy






How much energy is consumed?
What energy carriers (e.g. electricity, gas, etc.) are used?
How much of each type of energy is consumed?
Where and why (for what) energy is used?
Can energy be saved?
Have any energy saving measures already been implemented?
Water





How much water is consumed?
Where and why (for what) water is used?
What are water quality requirements at different points of use?
Can water be saved / re-used?
Have any water saving measures already been implemented?
Table 10– Questions and issues to be addressed at the assessment stage
Plan



Selection of concrete measures that will be implemented.
Prioritization.
Setting up a detailed plan outlining objectives, responsibilities and monitoring.
Implement


Implementation of a plan (concrete measures) and data collection systems.
Regular monitoring, measurement and control.
Review


Review of the systems in place.
Implementation of potentialchanges in order to continue the improvement loop.
The continual improvement cycle described above is very similar to PDCA approach (Plan – Do
– Check – Act) known from management system standards. When company already has an
environmental or other management system in place, it is advisable to incorporate resource
efficiency issue into it. Resource efficiency programme then helps to identify objectives and set
targets for such management system.
Mapping tools
When company decides to tackle resource efficiency within its processes, an initial analysis or
review is necessary to be done in order to understand the current situation including potential
sources of inefficiency and negative environmental impact.
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For smaller enterprises and operations, visual tools that help easy understand the processes,
its inputs and outputs, and resource efficiency and environmental issues can be utilized. The
following two can be recommended:


Eco-mapping;
Waste mapping.
Eco-mapping
Ecomapping is a step by step process to gather useful information and to trigger
environmental actions. Its purpose is to provide (small) companies and organisations with a
visual, simple and practical tool to analyse and manage their environmental behaviour.
As 80 % of environmental information is location-based [5], developing “ecomaps” of
company’s area can be very useful. They point to inadequate behaviour, problems with
equipment, work floor arrangement and lead to the identification of environmental
impacts.They show what is happening and where.
Usually two kinds of maps are produced:


Map of the urban situation – map of the site, seen from above, including car parks,
access areas, roads and the surrounding environment.
Maps of the shopfloor – maps of the site to scale showing the interior spaces,
integrating significant objects (e.g. machines, boilers, etc.). Each map addresses
different environmental issue (e.g. water map, waste pam, risks map, etc.).
Figure 11– Example of ecomap - water consumption and wastewater system (source: [5])
More information can be found at Ecomapping portal [4]; steps of ecomapping
implementation are described in the publication [5].
Waste mapping
Similarly to ecomapping, the Waste Mapping tool has been developed to help companies easy
understand material flows within their processes and waste they generate.
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Figure 12– Example waste map for printer (source: [7]).
Once waste sources are properly identified, it is necessary to include some figures – how much
waste is generated, what type of waste, how much does it cost, etc. in order to identify the
most important flows and sources to be dealt with.
More information including practical guide how to develop a waste map can be found in the
publication [6].
4.10.5 Implementation of 5S
To implement principles of 5S strategy





Sorting; Eliminating all unnecessary equipment (tool or parts) from the work area. The
work area is audited so that any unnecessary items are removed and those that
remain are prioritized and stored in easily accessible locations.
Straightening; To reduce time wasted in looking for equipment tools, parts or
instructions are ordered so that the most frequently used are the most accessible.
Sweeping; Clean all equipment and organize the workspace so that all equipment has
a designated storage location. At the end of each shift the equipment and workplace
should be left clean and everything returned to its storage location.
Standardizing; All work stations where a similar job is being conducted should be
identical so that an employee working in one location will be able to conduct the same
task at a different station with the same tools.
Sustaining; Having introduced the new system it must be maintained and become the
new way to operate. The new way of operating should be maintained and reviewed
and improved, suggested improvements should be reviewed in accordance with the
first 4 steps.
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ANNEX. TEST AND WORKSHEETS
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ECOFLEXOBAG Control Elements_FB.2.1
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ECOFLEXOBAG Specifications Form_FB.2.2
FORM FB.2.2
Printing Specifications
Process
Parameter
Specification before
implementation
Specification after
implementation
Relief
Angles for process colour printing
Screening
PRINTING FORM
Dot shape
Printing form hardness
Plate surface tension
FORM FB.2.2
Printing Specifications
Process
Parameter
Specification before
implementation
Anilox geometry
ANILOX
Anilox screening
Cell shape
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Specification after
implementation
FORM FB.2.2
Printing Specifications
Process
Parameter
Specification before
implementation
Specification after
implementation
Hardness of adhesive tape
PLATE MOUNTING
Composition of sleeve
FORM FB.2.2
Printing Specifications
Process
Parameter
Specification before
implementation
Ink viscosity
Ink pH
INK FORMULATION
Ink solid content
Colorimetric reference
Tolerance
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Specification after
implementation
FORM FB.2.2
Printing Specifications
Process
Parameter
Specification before
implementation
Inks pH
Inks Temperature
Inks Viscosity
Production Speed
Dryer Settings
Corona Treatment (Critical for
Water Based Inks)
Anilox Volume (A banded Anilox
should be used)
PRESS OPTIMIZATION
Lower tone gain
Smallest text reproduced
Minimum line widths reproduced
Visual Quality of Images
Visual homogenity of solid tones
Register
Slur
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Specification after
implementation
ECOFLEXOBAG Press Optimization Test Form_FB.2.3
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ECOFLEXOBAG Banded Anilox Test _FB.2.4
pdf.
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ANNEX. SUMMARY OF
SUSTAINABLE PRINTING
PROCEDURE
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Excel Sheet
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ANNEX. FLEXOGRAPHY INKS
PROPERTIES
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Measuring the physical properties of inks and understanding how these are affected by the
choice of ingredients is a large part of ink technology. Formulating inks requires a detailed
knowledge of the physical and chemical properties of the raw materials composing the inks,
and how these ingredients affect or react with each other as well as with the environment.
Flexographic printing inks are primarily formulated to remain compatible with the wide variety
of substrates used in the process. Each formulation component individually fulfils a special
function and the proportion and composition will vary according to the substrate.
Ink Components
A functional flexographic ink must exhibit several qualities. It needs to produce a color or other
visual effect. It must adhere to the material being printed (the substrate). It must withstand
conditions to which it will be exposed in practical use, such as chemicals, abrasion, and
extreme temperatures. Finally, it needs to produce a consistent finish.
Different types of ingredients contribute to a successful ink. Five types of components allow
ink to adhere to a substrate and produce its visual effect. The solvent provides fluidity, which
allows the ink to be transported from the ink fountain to the substrate. The colorant, which
can be either a pigment or dye, provides the color associated with ink. The resin causes the ink
to adhere to the substrate, among other traits. Additives modify the physical properties of the
inks, such as flexibility and the coefficient of friction.
Colorants; Colorants are compounds that reflect and absorb certain wavelengths of light.
Wavelengths that are reflected by a colorant are seen by the eye and perceived as colors. The
two types of colorants used in printing are dyes and pigments. Dyes dissolve into the liquid
solution. The most common dyes are basic, amino-based compounds. The transparent
properties of dyes can be beneficial when transparency is desired, and the colors of dyes are
often quite strong. However, dyes can be damaged by chemicals and water, and they can also
be toxic. Pigments are small, insoluble particles. They can be made from a wide range of
organic and inorganic compounds, and as a result, have a variety of properties. Particle size
and chemical stability are two variable properties that can yield differing ink characteristics. In
general, pigment-containing inks are more resistant to chemicals and heat and are less prone
to bleeding through the substrate than dye-containing inks.
Resins; Resins cause ink to adhere to the substrate, disperse the pigment, and provide gloss to
the finished coating. They also can impart differing degrees of flexibility, scuff resistance,
cohesive strength, block resistance, and compatibility with the printing plates. Resins are solid
compounds that are soluble in the solvent and often have complex molecular structures.
Common categories of resins include nitrocellulose, polyamides, carboxylated acrylics, and
polyketones.
Additives; Several components can be added to inks to improve the performance of the
finished products. Examples include plasticizers, which enhance the flexibility of resins; waxes,
which enhance slip, rub and scuff resistance; wetting agents, which modify the surface tension
to improve adherence to substrates; and defoaming agents, which in water-based inks reduce
soap-like effects.
Solvents; Solvents are important in delivering the ink to the substrate. The solvent allows the
ink to flow through the printing mechanism, and then evaporates so that the ink forms a solid
coating on the substrate. Typically, inks are manufactured and transported in a concentrated
form, and the printer must add solvent to the ink to attain the desired viscosity. A solvent must
display several important characteristics. It must adequately disperse or dissolve the solid
components of the ink, but must not react with the ink or with any part of the press. It must
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dry quickly and thoroughly, and have low odor. Finally, it is desirable for the solvent to have
minimal flammability and toxicity concerns.
Common solvents in solvent-based inks include ethanol, propanol, and propyl acetate. In
water-based inks, the solvent is water, which is amended with alcohols, glycols, or glycol
ethers. UV-cured inks are different in that they do not have solvents per se, in that the
chemicals are not added with the intention of being evaporated after application of the ink.
Fluidity is provided by liquid, uncured components of the ink, such as monomers, which are
incorporated chemically into the ink upon curing, instead of evaporating7.
For environmental and health reasons the use of traditional organic solvents has gradually
been replaced by water and non-volatile products. In the context of the production of Plastic
Commercial Bags within ECOFLEXOBAG Project, solely water-based inks are considered.
The main focus of substitution of solvent based inks has been replacement with water based
ink. Water-based ink, where the solvent content is replaced with water, has the advantage of
significantly reducing solvent content although water based inks will typically contain a small
proportion of solvent. Further solvent reduction is achieved through the use of water-based
cleaners however in practice solvent cleaners are often used, especially where inks have dried.
As water has a lower volatility than solvents used in inks, the drier power requirements are
higher which can limit production speed for existing installations. The higher power
requirements are however off set due to removing waste gas treatment and the ease of
recirculation to the facility. Water-based inks are often less flammable than solvent-based inks
and are thus easier to store and use.
Water based inks can be used to print with the same production speed, efficiency and quality
as solvent based inks onto both paper and film substrates however film substrates may require
pre-treatment (e.g. corona) to achieve acceptable ink transfer
There are many conflicting opinions, however the performance of water based ink has
improved and can now match that of solvent based under optimum conditions for each
process. There is often a steep learning curve for printers switching to water based ink from
solvent and therefore the immediate impression is often that speed and quality is reduced
however when training/experience is gained improvements follow. There is a wide range of
variables that must come together to produce a high quality printed image and therefore it is
very difficult to make a statement between ink technologies in isolation (not to mention
variations in quality within an ink type). With a much larger pool of expertise, experience and
therefore confidence when using solvent based inks added to the greater tolerance to changes
in substrate it could be stated that there is a greater probability that a higher quality will be
achieved when using solvent based inks. Also in many situations it is only possible to achieve
the desired outcome when using solvent inks, e.g. for fluorescent effects, gold or silver colours,
or where very high gloss is required (BREF)
Typical water-based flexographic formulations for printing on non-absorbent and absorbent
substrates are shown in Figure 12.
7
EPA 2002. Flexographic Ink Options: A Cleaner Technologies Substitutes Assessment
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Figure 12 Typical water-based flexographic formulations8.
Printing inks are composed of a colorant (pigment or dye), and a vehicle. The great majority of
flexographic inks manufactured today are pigment-based, but dye-based inks are still made for
particular purposes. The purpose of the pigment or dye is to provide the image contrast on the
substrate and aid desirable properties, such as light resistance and gloss. Pigments and dyes
are obtained from both natural and synthetic sources and are either organic or inorganic
compounds.
In contrast to dyes, pigments are insoluble in the ink vehicle. The pigments used in a given ink
have a major effect on the viscosity and flow properties of the ink, and different pigments can
influence the same vehicle system in quite different ways.
When ink is manufactured, it is extremely important to ensure that the pigment is properly
dispersed. If the dispersion of the ink is not carefully controlled, most of the other properties
of the ink will be negatively affected. This includes properties such as color, gloss, strength,
viscosity, yield value, rub resistance, and other general printing properties. The thinner the inkfilm weight being applied, the better the dispersion must be.
A flexographic ink vehicle consists of resins (binders), solvents and additives. The purpose of
the vehicle is to carry the pigment to the substrate, hold it there and provide properties such
as transfer behavior, setting, drying mechanism, gloss and rub resistance. The formulation of
inks in terms of which type of vehicle and/or resin is used depends upon the printing process
and the properties required of the finished printed product.
A number of resin systems are used in water-based inks and a blend of resins are commonly
added to give a balanced range of properties. The dual requirement for these resins is that
they retain water solubility while being printed but becomes water insoluble after printing
and drying. Some resin systems are designed with colloidal dispersions, usually of acrylic
resins, that are made water-soluble by the addition of a volatile base, normally ammonia or an
amine, to the correct pH. After printing, the base is volatized and the print achieves a measure
of water resistance. These resins generally have high gloss and provide good pigment wetting
and printability. An example of a very important drawback, however, is poor resistance,
especially towards alkali. To overcome this problem, resins with aqueous dispersions or
emulsions, also usually of acrylics, are used. These are water insoluble polymers dispersed as
tiny droplets in the aqueous phase. After printing the emulsion particles coalesce to form a
continuous ink-film exhibiting very good print and product resistance properties. These softer,
low-Tg (glass transition temperature) acrylic emulsions are used in water-based inks to give
adhesion and flexibility to non-absorbent substrates.
8
Maria Rentzhog. YKI, Ytkemiska Institutet AB. 2004. Characterisation of Water-Based Flexographic Inks
and their Interactions with Polymer-Coated Board
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Resolubility; A very important property for flexographic inks is the resolubility of the ink, i.e.
the ability of the dry polymer to be redissolved by the same polymer in the wet state. This
resolubility is essential for a good machinability of the ink or else it will permanently dry in the
anilox cells during printing. Emulsions, when used alone, can give problems with resolubility
and drying-in, and in order to improve resolution it is normal to include some alkali-soluble
resin, which exhibits very good resolubility.
Drying; Drying in water-based flexography is only by evaporation when printed on nonabsorbent substrates, which is the case of Plastic Commercial Bags. The properties of the ink
are also modified and improved by the use of various additives, for example plasticizers,
waxes, and anti-foaming agents. Additives provide special effects, such as low or high
coefficient of friction, or rub resistance.
Surface tension and wetting processes; Water-based inks share many common features with
solvent-based inks. However, aqueous inks also present a range of characteristic differences
and in some cases difficulties not seen with solvent-based inks. One of these is the higher
surface tension of water-based inks compared to solvent-based inks.
For water-based flexographic printing, the surface energy of the substrate relative to the
surface tension of the ink is very important. When the ink comes into contact with the
substrate, the strength of the forces acting between them will determine what happens at the
interface. Wetting occurs when the forces cause the ink to spread and non-wetting when no or
only partial spreading takes place. Besides the wettability of the substrate surface, other
properties such as transfer and adhesion of the ink to the substrate are dependent on the
surface energy of the substrate as well as the surface tension of the ink.
Water has a surface tension of 72 mN/m, while solvents typically have surface tensions of
slightly above 20 mN/m. Therefore, it is necessary to use co-solvents, slower amines and
surfactants in water-based inks to lower the surface tension below 38 mN/m in order to
improve wetting of substrates and printability. Hence, the term water-based ink does not
mean that it is solvent-free. Environmental regulations, however, require the minimization of
volatile organic compounds (VOC) in water based systems and thereby limit the use of volatile
alcohols used in water-based inks.
Ph; The degree of water reducibility or water tolerance depends on the pH value of the waterbased ink and a good pH control and balance is required. An ideal pH for water-reducible inks
is between 8 and 8.7. If the pH is too low, the water reducibility of the ink and stability with
water is greatly reduced. A too high pH, on the other hand, can lead to the printed ink not
achieving adequate water resistance after it has dried. Therefore, it is essential to control the
pH of these inks within strict limits.
Viscosity ; The viscosity and yield value of a given flexographic printing ink are important
properties and must be controlled within quite narrow limits if consistent and reproducible
printing results are to be achieved. This is because the distribution, transfer and working
properties of the ink on the press are greatly influenced by variations in these properties. The
flow of the ink from the duct, the transfer down the press, and the eventual printing of the ink
from the printing plate on to the substrate, is all influenced by the viscosity of the ink. The
proper viscosity will depend on a number of factors such as press speed, substrate, type of
metering, temperature, solvent mix and print thickness required.
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ANNEX. FLEXOGRAPHY QUALITY
PARAMETERS
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A. Printing quality parameters
Solid ink density
Description: Solid Ink Density measures the light absorbing property of a printed ink. It is the
reflected value of a solid spot of colour measured with a densitometer (or
spectrodensitometer) using a specific filter with a specific light source. For example, 1.35 is the
target density for cyan ink measured through a red status T filter with a D-50 light source on a
determined substrate. A higher density indicates more light is absorbed; therefore, a darker
surface, therefore cyan appears darker. Printing houses should standardize the densities for
every used substrate material. Therefore the press should be characterized prior for every
substrate material.
By running to the press characterization, the printer can consistently match the contract proof,
provided the prepress provider has applied the correct characterization data. When printing all
optimization/fingerprint/characterization trials, the printer should set up and run under
preestablished conditions, just as a production job.
Test Element: The SID patches should remain at 100% regardless of the maximum screen value
used in lieu of a solid in the image.
Each patch must be slightly larger than the densitometer aperture to ensure accurate
measurement. The target must be imaged onto the plate simultaneous to the "live" image.
Figure 13 Example for the Solid ink density test element.
Print contrast
Description: Print contrast is calculated using the 70% tint patch and the 100% solid patch of
each process colour. It is expressed as a percentage and indicates the ability to hold shadow
detail. The goal is to print the highest print contrast possible.
Test Element: To measure print contrast, the 100% solid and 70% tint patches are required
along with a spectrodensitometer. The patches must be slightly larger than the
spectrodensitometer aperture to allow accurate measurement. The target must be imaged
onto the plate simultaneous to the “live” image.
Figure 14: Example for the “Print contrast” test element with 100% solid and 70% tint patches.
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Ink trap
Description: The ability of one ink to lay smoothly over the next is referred to as “ink trap”.
Process printing requires each colour to overprint the previous colour in order to produce
desired secondary and tertiary colours. Generally, a trap of 80% or better is considered
desirable. However, the achievable trap will vary based on press conditions.
The trap is calculated by measuring the density of overprint and comparing it to the density of
the individual inks using the Preucil formula (equation 1). The higher the trap value the better
the overprint with a trap of over 80% desirable.
Equation 1
𝑜𝑣𝑒𝑟𝑝𝑟𝑖𝑛𝑡 𝑑𝑒𝑛𝑠𝑖𝑡𝑦−𝑓𝑖𝑟𝑠𝑡 𝑑𝑜𝑤𝑛 𝑖𝑛𝑘 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
% Trap = 100 ∗ 𝑠𝑒𝑐𝑜𝑛𝑑 𝑑𝑜𝑤𝑛 𝑖𝑛𝑘 𝑑𝑒𝑛𝑠𝑖𝑦−𝑠𝑢𝑏𝑠𝑡𝑟𝑎𝑡𝑒 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
Test Element: Two and three-color overprints in combinations of CM, MY CY and CMY are used
to evaluate ink trap. If a screen value less than 100% produces the highest density, the
overprint patches should contain that screen value. Each colour solid ink patch is also required
in order to calculate ink trap percentage. The print sequence must be recorded. Each patch
must be slightly larger than the densitometer aperture to ensure accurate measurement. The
target must be imaged onto the plate simultaneous to the “live” image.
Figure 15: Example for the “Ink trap” test element.
Dot Gain
Description: If the printed image is to match the contract proof, the printer must achieve
consistent dot reproduction. Measuring and controlling dot area/dot gain enables the printer
to achieve similar results during production runs as realized during the press
fingerprint/characterization trials.
Dot gain is a consequence of dot and substrate deformation in the printing nip and a spreading
of the ink. The flexographic printing form is compressed in the printing nip and the consequent
enlargement of the dot on the plate produces a larger dot. The spreading of ink around a dot
in a half-tone area and the deformation of the dot mean that the printed dot becomes larger
than the original dot, which the printing process strives to replicate. The combined effect of ink
spreading and expansion of the print form is called the “physical dot gain”, which is the
difference in size between the printed dot and the dot on the plate. In addition the “physical
dot gain” there is an “optical dot gain”, due to lateral light scattering in the substrate (Figure 56). Optical dot gain is always present when print is viewed (perceived or measured) under
reflected light.
The total dot gain may be assessed from measurements of the reflectance factor of the halftone print R in relation to the reflectance factor of the corresponding solid print Rv and the
reflectivity of the unprinted paper R∞.
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Figure 16: Example for the “Ink trap” test element.
Test Element: Tone scales contain patches of flat tints from highlights through shadows. Tint
patches slightly larger than the aperture on the colour measurement device are required to
measure dot area & dot gain. The target must be imaged onto the plate simultaneous to the
“live” image. The selected tint values and number of patches will vary based on the
information required and the space available.
Dot gain should be controlled during Optimization/Fingerprint/Characterization Trials and also
during Production Run;

Optimization/Fingerprint/Characterization Trials: An extended tone scale containing
patches from highlights through shadows for each process colour should be included
on all print optimization, fingerprinted characterization trials. These tint scales provide
the raw data necessary to create dot gain curves and compensation curves.
Typically, tints of at least 2%, 3%, 4%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%,
95%, 100% should be included. In addition to the extended tone scales, the Printer's Scale
described below should also be included on all press trials to allow for repeatable press set-up
and run conditions.
Figure 17: Example for the “Ink trap” test element.

Production Run: On production runs, it is critical to measure and control both dot gain
and solid ink density.
 Selecting Tint Patches: At a minimum, for each colour, a solid patch and the tint patch
that is most sensitive to pressure adjustments as determined during the press
fingerprint trial should be included on all production runs. Space permitting, it is
desirable to include additional tint patches to allow for better control and monitoring
of the printed image. Consult the printer to identify the appropriate tint patches.
 Types of Tone Scales: It is recommended using tone scales to control both the
platemaking process as well as the printing process. There are multiple approaches ,
and depending on the application, one or more may be appropriate. [11]
Total area coverage
Also known as “Tone Value Sum” in ISO documentation, total area coverage (TAC) is typically
measured in the darkest shadow area of a process image by adding together the dot
percentages of CMYK in the file or on the final films. For example: If C, M, Y and K each equal
75%, the total area coverage is 300%; if all four process colours were printed solid, TAC would
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be 400%. TAC is one of many parameters that can be fed into a colour management system in
order to build a profile used for separating images for a specific print system. Total area
coverage is measured in the full colour file prior to platemaking.
The objective of TAC is to extend the tonal range in the shadow region while minimizing ink
film thickness. Higher TAC values may result in ink trapping and drying/curing problems,
resulting in slower press speeds.
Another consideration is cost. Applying additional ink that does not result in a darker shadow
drives cost without improving quality.
A Total Area Coverage (TAC) Test Element is a grid that contains increasing dot percentages of
black going down each row and increasing dot percentages of CMY moving from left to right
across each column. The TAC value is listed in the bottom right-hand corner of each patch.
Evaluate this test element by visually, or densitometrically, assessing each patch to identify
when increasing the TAC value does not result in increased darkness, or density. The square
with the lowest TAC value and highest density is the optimum TAC value for the print condition
being evaluated. Printing with total coverage higher than the optimal value may cause
drying/curing issues forcing slower press speeds and increase ink consumption and costs
unnecessarily. The optimum TAC value will vary with the print condition (substrate, ink
chemistry, anilox, mounting tape, dryer configuration, press speed, etc.). [11]
Figure 17: Dot Area Test Element: Typically, multiple dot area scales, at varying line screens, are
included on the fingerprint trial to identify the optimum line screen for the print condition.
Because of the complexity of the variables involved, the Total Area Coverage chart is a ballpark
reference only. It is recommended including a TAC test element on the fingerprint press form.
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A.2 Printing Control Elements
The aim of process control at press side is to quickly achieve the desired colour results and
registration of the different process colours and spot colours. When the more important press
parameters, such as standardized printing plate production, dot gain, substrate and ink have
been determined, then it won’t take very long to balance the inking for the best possible
outcome.
Several Control Elements has been developed for printers as an aid to help balance the press
process in the best way possible by utilizing a standardized proof.
5.3.1 Process Control
Quality and process control elements are the tools to facilitate the superior and consistent
results printers expect and that their customers demand, both through each pressrun and
from job to job. When the printing process is controlled, the resulting printed pieces are
consistent and better in terms of productivity, quality, and cost. In addition, using quality and
process control products help to build customer confidence and satisfaction, increased
credibility, and, in turn, repeat customers. Following there are shown several printing control
elements for registration, slur, grey balance and colour matching.
5.3.1.1 Registration Control
When one word is printed in one colour and another word next to it is printed in a second
colour, register shifts can cause these two words to overlap or misalign. Due to this register
shift, different colour text should be more than twice the image trap dimension away from
each other.
Figure 19: Image Trap: When trapping two colours, FIRST recommends “spreading” or enlarging the
lighter colour under the dominant colour.
Proper image register is necessary to prevent unwanted colours and misalignments. The three
main uses of registration marks are to identify:



Position/location of the image on the substrate,
Colour-to-colour registration, and
Square to the lead edge of the sheet (corrugated).
Test Element: There are many different registration marks available for manual or automatic
assessment. Register marks belong on the left and right side of the image area and must be
imaged simultaneous to the “live” image. Registration targets are used for every colour – both
process and spot colours. When all marks are in register, the elements of the printed image
should be in register as well. The prepress provider and printer must agree on the type of
register mark for the print application before producing the job.
Figure 20 Traditional Registration marks.
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When space allows, it is recommended the use of the advanced RTT register marks because it
quantifies the exact amount of misregister without the use of a tape measure. This reduces the
time required to achieve register. Select the scale and tolerance that applies to the press. The
size and tolerance should be determined during the fingerprint trial. The objective of the RTT
target is to place the triangle (of each colour) on the centreline in both lateral and
circumferential directions. The longer scale lines at the centre of each target represent the
“natural variation” of the press (3 sigma). As long as each colour triangle remains between
these lines, the press is operating in tolerance. The target can be easily adjusted for the gear
pitch of the press, each line equalling the distance of 1 gear tooth. If the target does not fit on
the web, it can be embedded in the bearer bars.
Figure 21: Advanced RTT Registration marks.
5.3.1.2 Image Slur
Description: Optimum (kiss) impression is the minimum necessary pressure to transfer ink
from the anilox to the printing plate and from the plate to the substrate. Slur is a blurred
image, caused by over impression and sometimes mechanical press problems. Slur/impression
targets quickly and easily indicate when the condition exists.
Test Element: There are two types of impression targets: the hexagon and the star/flower
target.
Figure 22: Slur Control Element as Hexagon Target or Star/Flower Target.
The hexagon target is produced in two resolutions. One is used for coarse screen rulings under
85lpi, and the other is used for 100lpi and finer. The hexagon shape radiates from the centre
out and becomes progressively larger. The relationship between the line weight and the
distance between lines is critical. The line weight should be equal to 2/3 the distance between
two lines. These scales must be built to the appropriate size; reducing/enlarging the scales will
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alter the line weights. When an hourglass pattern appears in the hexagon, there is too much
plate to-substrate impression. The hexagon target can also indicate ink balance and drying
issues on press.
The star/flower target contains “petals” growing in width from the centre out. This target is
useful for monitoring anilox-to-plate impression. Over impression of anilox-to-plate results in
the centre of the flower filling-in. Under impression results in the middle of the flower not
printing. The size of the flower and the individual petals should be adjusted for anilox volume.
Higher volume anilox rolls require a larger target. The appropriate size target should be
determined during optimization or fingerprint trials. [11]
5.3.1.3 Colour Consistency
When printing a continuous tone image, the primary print characteristics that must be
measured and controlled are:
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solid ink density
print contrast
ink trap
dot gain
total area coverage
registration
image slur
All these characteristics are already explained. Other variables for the printer to optimize and
control include
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grey balance
colour control (Solid Ink Density),
A detailed explanation of each of these variables is provided as follows:
5.3.1.4 Grey Balance
Description: Gray Balance is the proper combination of cyan, magenta and yellow ink to
produce a neutral gray as measured by a densitometer. The actual dot percentages required to
produce a neutral gray must be determined during the fingerprint trial and press
characterization.
Test Element: There are two types of test elements used for gray balance: detailed formats
which are used for the optimization/fingerprint/characterization trials and reduced formats,
which are used for production runs.
Dot gain should be controlled during Optimization/Fingerprint/Characterization Trials and also
during Production Run;
Optimization/Fingerprint/Characterization Trials: These test elements are used to determine
the optimal dot percentage of C, M, Y to achieve gray balance across the tonal range. These
elements are utilized in the optimization, fingerprint and characterization trials. They include
highlight, quartertone, midtone, three-quarter tone and shadow dot areas. Within each of
these areas (blocks) there is a constant tint of cyan and varying tints of magenta and yellow.
Using a spectrodensitometer, the combination of tint values that best achieves neutral gray
can be determined. The size of the patches can be adjusted to conform to the space available
on the printed web. However, each square must be slightly larger than the aperture used on
the spectrodensitometer to allow for accurate measurement. This information may be used
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during the colour separation process to set neutral gray control points for each process colour
image. The test element can take a variety of shapes and forms. The following are two
examples. [11]
Figure 23: Gray Balance Test Elements: The target on the left is the P2P25X target which is used in
conjunction with the G7™ calibration technique. The target on the right is used to manually identify the
combinations of CMY that produce a neutral gray throughout the tonal range.
Production Run: The reduced test element is used to control gray balance during production
runs. Typically, there are gray balance patches for %-tone, midtone and 3/4-tone dot areas.
The patch on the left is black only; the patch on the right is the optimum combination of C, M,
Y to match the weight and neutrality of the adjacent black patch as determined during the
fingerprint and characterization trials. The size of the patches can be adjusted to conform to
the space available on the printed web. However, each square must be slightly larger than the
aperture used on the spectrodensitometer to allow for accurate measurement. [11]
Figure 24: Gray Balance Run Target: Determine the optimum percentages of C, M, Y during the press
fingerprint trial.
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5.1.5 Colour Control
Colour Control includes Solid Ink Density, Dot Gain and Ink trap which are already described.
However attached are shown the Control Elements to use in Production Run.
Figure 25: Control Element for Dot Gain, Solid Ink Density, Ink Trap, Gray Balance and Slur for Production
Print.
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References
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FIRST
Maria Rentzhog. YKI, Ytkemiska Institutet AB. 2004. Characterisation of Water-Based
Flexographic Inks and their Interactions with Polymer-Coated Board
EPA 2002. Flexographic Ink Options: A Cleaner Technologies Substitutes Assessment
Finding Cost Savings: Resource Efficiency for SMEs, WRAP, 2013
Resource Efficiency for Managers, WRAP, 2013
Saving Money Through Resource Efficiency: Reducing Water Use, WRAP, 2013
www.ecomapping.org
EMAS “easy” for Small and Medium Enterprises, European Commission, 2010
Waste Mapping: Your Route to More Profit, WRAP, 2013
Maintenance Best Practice Study: Productivity Maintenance in the UK Printing
Industry, Vision in Print, 2005
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