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The following documents contain technical presentations related to the
quantitative description and measurement of color. Click on their title to view the document in your Web-browser or
right-click to download. Except where noted, all downloadable files are in PDF format and require the free Adobe Acrobat Reader or Web-browser
plug-in, version 5.0 or newer. When opening a PDF document, you may receive a message
to the effect that it contains
information that your viewer cannot handle; you should disregard the message.
To
get Acrobat, click
here
or on the following image to go to the Adobe Web site:
APPLICATION NOTES
-
Light under control! (890 KB) (Written in collaboration with
Roger Breton)
We measured the characteristics of two fluorescent tubes designed for color
rendering, one light booth designed for both direct view and transparencies
viewing, and a
SoLux tungsten bulb designed to reproduce daylight. We
describe how to use the spectrum, the CCT, the chromaticity,
the CRI, the Quality Grade of daylight simulators (as per CIE
51 / CIE S 012), and the illumination uniformity data to evaluate an
illumination system. The document includes a presentation of ISO 3664
and its principal specifications.
-
AN-5 Taking back control of an IT8 7-4 file with wrong patch IDs
(674 KB) (April 2009)
Many IT8.7/4 files are saved with the patches in an order corresponding to
the random or visual layout, but with improper IDs. The problem becomes more
difficult to handle when the file was generated from measurements, and from
a random layout, where the rows may have been scanned backwards, or where
the rows were considered columns, and vice-versa. This Application Notes
shows how to use PatchTool to fix most of these files.
-
AN-6 Evaluating an ICC profile coverage of the Pantone and IDEAlliance data
sets (1.3 MB)
(April 2009)
A method, using PatchTool Gamut Tools Clip check, to evaluate if a list of
colors will accurately be printed by a press or printer. Examples are
given with the Pantone Coated and IDEAlliance SWOP Coated-3 data sets. The
application note includes an Appendix which provides additional information
on profile conversion accuracy.
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AN-7 The Optical Society of America Uniform Color Scales (OSA UCS) (517
KB)
(September 2009)
This very comprehensive Application Note describes the structure and
geometry of the Optical Society of America Uniform Color Scales (OSA UCS).
The document contains examples of how to navigate within this color space
and presents many color scales (color ramps) images which can be generated
with PatchTool. The document includes four mini-tutorials. In particular,
one tutorial shows how to generate a uniform list of colors which completely
fills the gamut of a device profile; such a list can then be used to check a
monitor's accuracy with PatchTool Display Check for instance. Another
tutorial shows how to compare the gamut of two devices in specific color
ranges.
Note: This Application Note can also be found as Appendix E of the
PatchTool Help manual (PDF
file).
RGB spaces
For the ones who want to gain a deeper knowledge of the
mathematics behind RGB spaces, here are three "equation heavy" documents. There is overlap in the theory content; this was done so that they are self-contained.
-
RGB coordinates of the Macbeth ColorChecker
(319 KB) (updated
and augmented
June 2006)
The RGB coordinates of the ColorChecker
in 4 RGB spaces (Apple, Adobe, ProPhoto, and sRGB), and
the method by which they were derived from L*a*b* D50 data.
For additional information:
ColorChecker_RGB_and_spectra.xls
(391 KB) (updated
and augmented
June 2006)
This Excel spreadsheet contains:
- RGB tables for 19
spaces, and L*a*b* (D50) values derived from averaged spectrums;
-
RGB tables for 19 spaces, and xyY
(D50) values derived from GretagMacbeth L*a*b* D50 data (2005);
-
RGB tables for 19 spaces, and L*a*b* (D50) values derived from CIE (1931)
xyY data (1976);
- Averaged spectral data with Standard Deviation
tables (from 20 charts);
-
Graphs of all the average spectrums with standard deviation
(the RGB spaces in this file are the same as the ones described in
BabelColor CT&A Detailed
Specifications).
For simulated (synthetic) images of
the ColorChecker in the 4 RGB spaces presented in the above document, as
well as in L*a*b* space, go to the
ColorChecker page.
-
A comparison of four multimedia RGB spaces
(560 KB)
Adobe (1998), Apple RGB, ColorMatch and sRGB compared. Which of
the last three has the largest gamut? The answer may not be what you think!
-
A review of RGB color spaces
(984 KB)
The complete process between spectral data and RGB coordinates, from xyY to
R'G'B', with a section on the various TV and multimedia display standards.
Color theory
The BabelColor CT&A Help file contains many sections dedicated to technical
information, including detailed equations for all color difference formulas
and conversion between color spaces (L*a*b*, xyY, etc.), and ten tutorials:
A series of articles in the
Metal
Finishing magazine (The articles used to be freely available on the
Web; they need to be purchased now, sorry!):
- Part 1:
The Color of Money. Basic concepts: light, the eye, the Observer, gloss, numerical
representations.
Volume 103, Issue 1, January 2005, p. 38-42
- Part 2:
Getting to Know the Language of Color. Color conversion, color decks,
color difference, FED-STD-595 explained.
Volume 103, Issue 2, February 2005, p. 36-39
A series of web tutorials in the
graphics.com web
site:
The RGB Code: The Mysteries of Color Revealed
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