Prepress in Regards to
Image & File Formats
Learning Lunch
Agenda
Image formats
What they are and what do they mean?
eps, tif, jpeg, gif, ai
vector v.s bitmap (raster)
high res v.s low res
When do I use which? What do I need when?
Images and color expectations:
CMYK, RGB, PMS & Index
The life of a PDF
What is the difference between editable and non-editable?
What is the difference between high & low res?
Can pdfs be sent to printers?
Comps v.s Mechanicals
Why low res is used in one, and high res in another?
How it relates to resource management.
Filenaming and the server
Most characters in a title
Common file formats
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IMAGE FORMATS
Image formats
What they are and what do they mean?
eps:
Meaning “encapsulated PostScript” (EPS), is a standard file format for importing and exporting
PostScript files. It is usually a single page PostScript program that describes an illustration or
entire page. The purpose of an EPS file is to be included in other applications. An EPS file can
contain any combination of text, graphics and images. Since it is actually a PostScript file
(PostScript is the primary language for printing), it is the most versatile file format that is
available. Vector based art that will be imported into a desktop program or into a photoshop
document to “raster” it. Also can send this to a printer for production. Can be a bitmapped image
but not typically.
tiff:
Meaning “tagged information file format” TIFF or TIF is, in principle, a very flexible
format that can be “lossless” (meaning no data is lost). The details of the image storage algorithm
are included as part of the file. In practice, TIFF is used almost exclusively as a lossless image
storage format that uses no compression at all. Most graphics programs that use TIFF do not
compress in order to maintain quality. Consequently, file sizes are quite big. Usually is bitmapped,
uncompressed art that will be imported into a desktop program. Also can send this to a printer for
production if 300 dpi.
gif:
Meaning “graphic interchange format” which saves bitmap images at 8 bits per pixel and caps the
color at 256. The 8 bit level allows the image to work across multiple server platforms. This does
compress the image when saving so some color information and quality
may be lost. These are used for web and powerpoint only.
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Image formats
What they are and what do they mean? Cont.
jpeg:
Meaning “joint photographic expert group”. Named after the group that created it, this format is
for raster or bitmap images. Its compression factor stores the image on the hard drive in less
bytes than the image is when it displays, making it ideal for the web, email and for powerpoint.
You will lose some quality in saving down to a jpeg because of the compression.
ai:
Short for Adobe Illustrator file, this is a file created in Adobe Illustrator as a vector
based image with bitmap images placed within it. This file is not an importable image.
It does not compress. Usually, “Virgin” working vector based Adobe Illustrator file is needed by
anybody that is going to work on the file, trap it, print it. Must have the Illustrator program to
open, and not importable.
psd:
Short for Adobe Photoshop file, this is a file created in Adobe Photoshop as a raster based image.
Often, this file is complex with all its layers and pieces. It is often called a “virgin” file, kept in this
format as a working, editable file with no compression so all the information stays intact. This file
is not an importable image. It does not compress, in fact, is often VERY large.
pdf:
Means “Portable Document Format” is a universal file format developed by Adobe®
that preserves all the fonts, formatting, graphics, and color of any source document,
regardless of the application and platform used to create it. Because of its name
“portable” you will find PDF a very common format which is widely used on the
internet due to its platform independence. To view PDF files you need Adobe Acrobat
Reader which you can download free. You can save these as high res for
printers or low res for just viewing. Sometimes, you can open in Illustrator.
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Image formats
Vector v.s Bitmap?
Vector Images:
Vector images are images that are completely described using
mathematical equations, made up of lines and points with lines
interconnecting all of them or just a few.
It is these lines that are saved when saving a vector image, so
the file size is very small.
Because this art is based on lines v.s pixels, these images are
very scalable without losing quality, making them perfect for
company logos, maps, and other objects that need to be scaled
down frequently. They are usually saved as .eps files. Because of
the linear quality of these files, resolution is never an issue. They
are easily reproduced and easy to prepare for printing.
Image formats
Vector v.s Bitmap?
Bitmap (raster) Images:
Bitmap images are completely made up of colored dots or pixels. As you can see, the
image consists of thousands of rows and columns of pixels. The human eye can’t see
these pixels, so to us, everything looks smooth and tonal. You can have all kinds of
bitmap images (see pic.)
The pictures you take with your digital camera are bitmapped.
Bitmaps can be very large because of all the pixel data that needs to be saved, but
depending on what format (JPEG, GIF, TIF) you can control and compress the size.
However, you need to keep in mind how large your bitmap images need to be.
Bitmap images get pixilated and blocky if enlarged too much. Also, low-res images
for printing becomes very pixilated and blocky, so it is important to use the best
quality image possible for reproduction. But remember, more dpi (dots per inch)
means more memory, so file sizes for printers can get slow and very large. Typically
these high-res files are not e-mailable.
Image formats
Low-res v.s High-Res in bitmapped images?
Low-Res: Typically, art directors and designers work in low res files for a concept round
(typically 72 dpi-150 dpi). This allows for creative depth-to focus on getting as much
ideation done as possible in a short time without worrying about production files and a
slow computer. These files would never be acceptable to a printer, but are passable for client
presentations, e-mailed layouts and for powerpoint. The file sizes tend to be smaller, but the
quality is a little bitmapped. The trade off is we get a larger range of work and approaches.
High-Res: Typically, high-res images are 300 dpi in size. Often this is needed for the best
print quality. 300 dots per inch however tends to be a very large file, and depending on
how big the finished piece is, the file could be 65 MB to 2GB. This is to ensure the image is
smooth and crisp and you see no pixilization. Printers will ask for 300 dpi files. You cannot
take a low-res (72) dpi image and just res it up. The digital information (the pixels) are not
there to begin with. Res-ing it up doesn’t necessarily add more pixels. So for the best print
quality we need the highest resolution file we can get from our clients, the stock houses
and photographers.
Image formats
A word on fractals, it may save your client’s butt
Your client gives you the only image they have, and it is not big enough to res up for
a tradeshow. It is all they have, and they won’t budge on using something else.
Enter Genuine Fractals®.
It’s based on CRAZY math. GF transforms the image into "resolution independentassets" eliminating the relationship between pixels and resolution. The image
becomes mathematically encoded as an algorithm and the pixels of the original raster
image are replaced with a new file structure that stores the entire image and none of
the pixels. When you open the image again, you can re-scale it to the desired size
and the algorithm will generate new pixels while maintaining sharpness regardless of
image size.
Images & Color
Expectations
CMYK, RGB, PMS & INDEX
CMYK
CMYK: This is the format for most print art and imagery. For the
most part photography must be duplicated in the CMYK format.
This consists of dots of cyan, magenta, yellow and black. Different
percentages of them make up all the colors of the spectrum. The
color range in CMYK is much shorter than an RGB range-because
RGB is the based on the light spectrum.
This is important to know when converting RGB files to CMYK. One
needs to be sensitive to a color shift that will occur because you
are using less color range to match the RGB in CMYK-land.
FORMATS: TIFFS, PSDS, EPS & PDFs
CMYK, RGB, PMS & INDEX
CMYK cont.
CMYK: Because “dots” make up CMYK printing, registration
is really important (metal plates make dots layered on
each other seamlessly to print things). Also, small type in
a color with conventional printing is difficult to hold
registration. SO keep it one plate color, or reversed.
CMYK is a smaller color spectrum. SO to have it match
PMS is very difficult (more on this) Because of this, agency
position is to work with CMYK chips only. In branding, we
will deliver PMS matches as well. But printing PMS is costly
and used only for company’s that can afford it or their
brands are more “tightly held.”
CMYK, RGB, PMS & INDEX
RGB
This is the format that is based on screen color (light). Your TV
and your monitor thinks in RGB and shows color in RGB.
RGB stands for Red, Green and Blue. It is ranges of these three
colors that will give you a variety of different colors. This format
is ideal for Powerpoint, online viewing of layouts, websites and
other light based sources. Digital photography is taken in RGB,
to give the greatest amount of color information to the file.
RGB gets a great range amount of color v.s CMYK. It gives you
more room to move around in your photograph when converting
to a CMYK format which has less. If you start out with more
“Information”, you are better off when it is time to prepare files
for printing. FORMATS: JPEGS, PDFs & GIFS
CMYK, RGB, PMS & INDEX
RGB
“Matching” then is a huge issue. Be aware that pdf viewing is
different than printing. The vibrancy they see on a monitor will
not hold in traditional printing. Art directors must match
whatever the client approved as close as possible using the
printing process that is being used as a guide. Therefore, what
might be in the file for “comp” and design might not indeed be
the final color mix in the final file that goes to print. This is
especially important when developing brand architectures (logo
color and approved palettes for the client)
CMYK, RGB, PMS & INDEX
PMS
What it is is what you get.
This is a line color system of flat inks. There are no variety of colors that
mix together to make it. The color of the ink for printing matches the chip
in the PMS book. These are colors laid down by one plate per color. Think
of when you go to the store and pick up paint for your walls. It should
never deviate. Your can is one color and matches your chip. The more
colors “plates”, the more money.
You can use screens of a PMS color, and you can hold color in registration
of small type because the type is not made of dots or a mix.
Matching a PMS color in CMYK is difficult, because even PMS is out of
CMYK’s range. (see gamut and chip book.)
PMS is not for a projects with full color imagery, but more simple designs,
logos and such. If a big brand wants a consistent red no matter where, a
PMS color may be the way to go.
FORMATS: EPS, PDFs
CMYK, RGB, PMS & INDEX
INDEX COLOR
This is reduced color mapping of 8-bit or less. This is done to reduce
images to their smallest size and these images are most commonly
used on Web pages as they are small and quick to load. The 256
color palette is mapped for best results on the Internet, taking into
account the differences between the Windows and Macintosh color
palettes.
When an image is encoded in this way, color information is not
directly carried by the image pixel data, but is stored in a separate
piece of data called a palette: an array of color elements, in which
every element, a color, is indexed by its position within the array.
The image pixels do not contain the full specification of its color, but
only its index in the palette.
The palette itself stores a limited number of distinct colors;
4, 16 or 256 are the most common cases.
CMYK, RGB, PMS & INDEX
Why do you care? This is for the art people!
If your client needs to match their brand colors perfectly in a
print job, suggest using pantone colors. Otherwise, matches are
never exact in CMYK. If it is a CMYK job, suggest doing a 7 color
job with an added PMS color plate and budget accordingly.
Photos are always shot in RGB, so conversion to CMYK will need
tweaking and randoms and proofs. So budget accordingly in
prepress money.
Manage client expectations on image conversions and color.
Talk to your art team about what the client is approving
against so we can make sure we choose colors in prepress
that meets expectations (Fiery? Pdf monitor? Proof?).
The Life of a PDF
PDFs
What is the difference between editable & non-editable PDFs?
PDFs are not readily editable in Acrobat - and editing may be
explicitly prohibited. A precise snapshot, a PDF file is created at
a specific date and time, and in a specific way.
If a PDF is editable, the maker has selected various fields using
Acrobat in which someone can go in and “edit” or “fill-in” certain
areas, like a form of some sort. Generally, images and graphic
text are not editable in a pdf.
Now, all this being said, done properly, a PDF can be opened in
Illustrator and edits can be made to it to some extent.
Sometimes not all the information translates correctly,
depending on what application the original document was
created from. If the document was made in Illustrator then
converted to a PDF, than it most likely can be reopened in
Illustrator and worked on.
PDFs
What is the difference between high-res and low-res PDFs?
PDFs can be saved out in various compression formats and
resolution, depending on the end user. A PDF can be saved out
to be the correct resolution for a printer to use and print from,
but the size of the file will be large. A low res pdf is lower quality
but can be saved to be small enough to e-mail to a client. These
low res PDFs cannot be judged on crispness or color. They
should not be any larger than 4 megs for e-mailing (sometimes
smaller, depending on your client’s inbox capacity).
Can PDFs be sent to printers?
Yes, but they will be large (not e-mailable)and they will need to
be a special, certified, printer friendly pdf, such as a PDFX1A,
etc.
Comps v.s
Mechanicals
What do they mean and why
is high res used in one, low
res in another?
What do they mean and why is high res
used in one, low res in another?
The answer to the above question is SPEED/RESOURCES, and
how it relates to the purpose of each phase.
Concepts need BREADTH of ideas, not depth. That may mean
something that does not exist yet and needs to be shot or
created. It may mean just a lot of stuff to be built quickly
without the burden of “heavy” files. Therefore things are
comped, low res to get approvals for creation and purchase.
Final is about depth vs. breadth. The files are meticulously
put together for flawless production. High res images
are put in the file. Time and detail is focused on the final
execution so it is perfect.
COMPS
This is the beginning phase of a project. We are often moving
quickly and we are just looking at ideas and possibilities.
(Breadth v.s. Depth). Often-times, because of the computer,
comps can look tight and pretty finished. This is not the case.
Often, these comps are directional and low-res. Imagery has
been thought through to a certain point, but not priced out.
MECHANICALS (also, old schoolers refer to them as “keylines”)
This is an old-fashioned word, heralding
the days when we used to do keyline and
paste-up and create “mechanicals”. These
mechanicals were shot by a camera to
create film, then plates for printing. This
used to be a meticulous process, and often
times a letter change meant sending out
for new type from the letterpress house. A
small change could take a week. Though
the process of keylining is obsolete, the
term is still used today to speak to the
process of creating a file for production.
MECHANICALS (also, old schoolers refer to them as “keylines”)
cont.
Now, this process is completely done on the
computer, which in many ways has been
wonderful, but has brought on new challenges
and new things to think about when we send
out a file to a printer. Though the timelines are
compressed, the meticulous process of
thinking through a file and making sure it is
correct to send out needs to be done, and Art
Directors and Production Artists need the time
to do it-because mistakes cost money.
MECHANICALS (also, old schoolers refer to them as “keylines”)
cont.
High-res needs to be placed with color corrections.
Copy needs to be proofed and finalized.
Files need to be set to printer specs with bleeds and live areas
accounted for and spec’d out.
Colors need to be spec’d. (Colors that a client has been looking at off
a laser and approved may not be the color that will actually show up
that way in a CMYK world).
Mark ups need to be created for the printer.
It will keep our productions costs down once our files leave
these four walls. It will also ensure that the client is getting
what they are expecting.
MECHANICALS (also, old schoolers refer to them as “keylines”)
cont.
Because mechanicals are high-res, the files are considerably larger, and processing times
get very slow. If you are working on a large format job, with high res images in place, the
file may take 5-10 minutes to save each time, and moves may take 5 minutes for the
computer to catch up. Some recent outdoor we produced took almost 20 minutes to save
everytime. So it is important to remember that timelines must ensure proper time for
production of files.
File Naming
FILE NAMING
Best practices for our server
Brevity is best
For cross platform compatibility keep your filenames (with extension) 31
characters or less [but preferably 11 characters or fewer]
Avoid spaces
Macintosh users like spaces. UNIX machines and URLs do not. In fact, system
10 on a mac will not let you add a space in a file name. Avoid them. In fact,
Fetch, a Macintosh file-transfer program used to upload files to servers,
automatically converts spaces to underscores when transferring files to UNIX
machines. The UNDERSCORE character is a good substitute for a space.
Spaces are BAD. Very Bad.
FILE NAMING
Best practices for our server
Avoid special symbols
Don’t use & # / \ : * ? “ < > | or other odd symbols in your file or directory
names. Also, putting a comma or semicolon in a filename could cause major
problems under various circumstances on any platform when working with
lists of filenames and should be avoided. The characters listed above are
frequently used for specific tasks in an electronic environment. For example, a
forward slash is used to identify folder levels in Microsoft products, while Mac
operating systems use the colon. Periods are used in front of file-name
extensions to denote file formats such as .jpg and .doc; using them in a file
name could result in lost files or errors.
Use lowercase characters only
Unless you have a compelling reason to do otherwise, strictly use lowercase
characters in file and directory names.
FILE NAMING
Best practices for our server
Give file names meaningful extensions
File name extensions are three or more characters that follow the file name
and are separated from the file name by a period. Extensions convey
information about the contents of a file and help Web browsers know how to
display or serve a document. For example:
index.html - An HTML file.
graphic.gif - A graphic file in GIF format.
newsletter.pdf - A newsletter in PDF format.
movie.mpeg - A video in MPEG format
Common file extensions
Raster Image Files Types and Formats
Audio File Types and Formats
Vector Image Files Types and Formats
Video Files Types and Formats
.bmp
.gif
.jpg
.png
.psd
.pspimage
.thm
.tif
.yuv
.ai
.drw
.eps
.ps
.svg
Bitmap Image File
Graphical Interchange Format File
JPEG Image File
Portable Network Graphic
Adobe Photoshop Document
PaintShop Pro Image
Thumbnail Image File
Tagged Image File
YUV Encoded Image File
.aif
.iff
.m3u
.m4a
.mid
.mp3
.mpa
.ra
.wav
.wma
Adobe Illustrator File
Drawing File
Encapsulated PostScript File
PostScript File
Scalable Vector Graphics File
.3g2
.3gp
.asf
.asx
.avi
.flv
.mov
.mp4
.mpg
.rm
.swf
.vob
.wmv
Page Layout Files Types and Formats
.indd
.pct
.pdf
.qxd
.qxp
.rels
Adobe InDesign Document
Picture File
Portable Document Format File
QuarkXPress Document
QuarkXPress Project File
Open Office XML Relationships File
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Audio Interchange File Format
Interchange File Format
Media Playlist File
MPEG-4 Audio File
MIDI File
MP3 Audio File
MPEG-2 Audio File
Real Audio File
WAVE Audio File
Windows Media Audio File
3GPP2 Multimedia File
3GPP Multimedia File
Advanced Systems Format File
Microsoft ASF Redirector File
Audio Video Interleave File
Flash Video File
Apple QuickTime Movie
MPEG-4 Video File
MPEG Video File
Real Media File
Shockwave Flash Movie
DVD Video Object File
Windows Media Video File
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Jacobs Agency