Color Theory and Training
1
Color 101
Color
Wheel
Basics
Mixing Primary Colors:
•
•
•
R + Y = Orange
R + B = Purple
Y + B = Green
Additive Color Mixing
Mixing Primary and
Secondary Colors:
•
•
•
•
•
•
B + G = Blue-Green
Y + G = Yellow-Green
Y + O = Yellow-Orange
R + O = Red-Orange
R + P = Red-Purple
B + P = Blue-Purple
Subtractive Color Mixing
Additive
and
Subtractive
Color
Mixing
Models
Used for creating color from light
• Mixing all colors will produce white
• Absence of colors will produce black
• TVs, Projectors, and Screens use this model
• Primary Colors are Red, Blue, and Green (RGB)
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Used to create color on physical surfaces
• Mixing all colors will produce black
• Absence of color will produce white
• Printers, Packaging, Signage, and Paint use this
model
• Primary Colors follow same as basic color wheel are
Cyan (Blue), Magenta (Red), and Yellow (CYMK)
Color Physics
Electromagnetic
Spectrum
• Light is made from energy
waves in the electromagnetic
spectrum
• The human eye can only
detect wavelengths in the
380 to 740nm range
• Red, Blue, and Green are the
predominant colors in the
visible spectrum
How we see
color
• Substrates act as a filter and reflect wavelengths make up the
corresponding color while absorbing wavelengths that are not.
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Color communication and color space
0
50
100
The brightness or darkness of color, 0 is black, 50 is gray
and 100 is white
0
100
Chroma is the amount of saturation in a color, 0 is gray
and 100 is fully saturated
L
100
Space
C
Hue is perceived color represented in degrees on the
color wheel
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H
3D
HUE
CHROMA
LIGHTNESS
3 Attributes of color
0
Color Tolerancing
Calculating the tolerance between two colors is like determining the distance between
two cities on a map.
• CMC – Tolerancing method that is based on L*C*h°, and provides better
agreement between visual assessment and measured color difference
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•
Delta E < 1 – Not perceptible by human eyes
•
1 < Delta E < 2 – Perceptible through close observation, however, if Delta
H > 0.75 will be become more apparent
•
Differences in lightness are less perceivable than differences in
chromaticity
Color Tolerancing – Delta E Examples
Only changes in lightness (no change in chroma and hue), color
difference not as perceivable than with changes in Chroma and Hue
Delta E < 2 not
perceivable
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Delta E < 1 not
perceivable, Delta E
= 2 slightly
perceivable
Delta E < 1 not
perceivable, but
Delta E = 2 is
perceivable
Color Under Different Light Sources
Incandescent light tend to
produce more red and
yellow than blue and green,
which makes them appear to
be “warm”
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Direct sunlight at noon is
considered a perfectly
balanced light source,
containing an equal amount
of all colors
Fluorescent lights produce a
cooler tone be producing
more blue and green
wavelengths
Fluorescent lights produce a
cooler tone be producing
more blue and green
wavelengths
Metamerism
A phenomenon wherein two colored samples will appear to be the same under one
light source but will appear different under a different light source.
• Products should first be evaluated under a D65 light source to ensure the color matches a
standard
• A second light source should be used to make sure that the standard and a sample color
varies the same way
• The goal is to make sure that a products color matches the standard color and also varies
the same way under different light sources.
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Color Evaluation Methods
Visual Inspection
Pros
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Light Booth
Cons
•
Cost effective
•
Subjective
•
Minimal Effort
•
Requires Training
•
Quick
•
Inconsistent light
sources
•
Cannot check for
metamerism
•
Dependent on
physical samples
Pros
•
Objective
•
Can check for
metamerism
Dependent on
physical samples
•
Minimal effort
Relatively
expensive
•
Quick
•
Cost effective
•
Minimal training
Consistent
lighting
•
Subjective
•
Can check for
metamerism
•
Requires Training
Minimal effort
•
•
Quick
Pros
Cons
•
•
Spectro 1
•
Cons
•
Intermittent
calibration
required
Spectro 1 - Introduction
*Calibration tiles should only be used on device with matching serial number
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Spectro 1 – App and Initial Sensor Setup
Step 1. Create Account
Step 2. Connect Device
Step 3. Select Sensor
Step 4. Pair Sensor
Make sure
Bluetooth is
enabled on
phone
Click
Create account
first to register
and pair device
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Spectro 1 – Home Depot Package Installation
Click
Click
Click
SCAN QR
CODE
OR
TYPE
IN CODE
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Spectro 1 –Spectro Settings
Click
After package
loads, click on yes
to download
package details.
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Spectro 1 – Spectro Settings
We will use
CMC 2:1 delta
E formula for
tolerancing
furniture colors
If any other settings are
different than the screen
above, follow similar
steps to change settings
to above
For color
communication
we will be
using LCH
values
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Spectro 1 – Scanning Color using Color Match
Luminosity, Chroma,
and Hue of scanned
color
Colors sorted by match with
smallest Delta E to largest
OR
Simple
explanation of
distance between
scanned color and
color in database
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*All colors in Home Depot package are colors being used by Home Depot. If Basic package is used, Color match
will show closest paint colors from different manufacturers to scanned color
Spectro 1 – Closest Match Data
Delta E of “closest match (Standard Color)” and
scanned surface
•
•
•
Reflectance – The effectiveness a surface of a material is in
reflecting radiant energy
Reflectance Curve - A plot of the reflectance of a surface as a
function of wavelength.
If the plots of both the closest match and the scan are very similar
then the Delta E will be very small
•
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Delta E of the “Closest Match”
and Scan can be low, but have
different curves (shown left).
However, the different curves
means that there will be
metamerism between the
standard and the sample at
that wavelength of light
Spectro 1 – Closest Match Data Continued
a
•
Lightness Scale – Shows
how light or dark the
sample is compared to
the reference color.
• This example
shows that the
“scanned color”
(the square) is
darker than the
standard color
(the circle)
• If the reference
color (scanned
color) is above
the standard
color (willow)
then the
reference color
would be lighter
than the
standard color.
b
-b
-a
•
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In the example shown, the “scanned color” is more red and
slightly more yellow than Willow.
• Corrections are made by adding colors that are
complimentary (colors that are across each other on
the color wheel).
• To correct the scanned color, you would want to
adjust by adding a little bit of blue and a little bit of
green to the paint of the “scanned color”
Spectro 1 – Calibration
Spectro 1 will require recalibration from time to time. Typically a recalibration should be done
around every 1000 scans, however, if the device does not seem to be performing properly a recalibration can be done to ensure to restore performance.
• Recalibration should be done using the calibration tiles that are located in the case
•
•
•
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Make sure when recalibrating the device that the S/N located on the back of the
calibration tile matches the S/N of the device
When performing the recalibration make sure that the tiles are clean and do not have
finger prints on them. If the tiles are dirty or have finger prints they can be cleaned off
using a soft cloth and some water. DO NOT CLEAN TILES USING ANY TYPE OF
CLEANING AGENT.
To perform a calibration go to the manage device page and click on “Calibrate Device,”
follow the prompts on the app to perform and complete the calibration.
Questions
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