Color Measurement
and Analysis
Attention ! Warning ! Important ! Read-me !
These pages are not really related to BabelColor. Well, they are in the sense that BabelColor software is well adapted to view, measure (on
display or prints), extract from images, and compare ColorChecker targets. They are not related in the sense that the ColorChecker is the
main subject of the page, that many products from other companies are mentioned, and because of the less informal tone used in the
presentation.
In fact, this page, on-line since 2004, simply exists because of my longtime interest in the ColorChecker.
But before we continue, just a small formality: ColorChecker is a registered trademark of X-Rite, and X-Rite is a trademark. OK, back to the
ColorChecker!
Comments welcomed!
Danny Pascale
colorchecker@babelcolor.com
A brief presentation
The ColorChecker Color Rendition Chart, this very well known chart with an array of 4 x 6 color patches, is an icon of the imaging industry. It
was formally presented in a 1976 article by C. S. McCamy (1924-2017) and his colleagues from the Macbeth Company, a Division of Kollmorgen
Corporation at the time:
•
C.S. McCamy, H. Marcus, J.G. Davidson, “A Color-Rendition Chart,” J. Appl. Phot. Eng., Vol. 2, No. 3, Summer 1976, pp. 95-99, Society of
Photographic Scientists and Engineers (Now called “The Society for Imaging Science and Technology (IS&T)”; https://www.imaging.org)
Copies of the article are not available in IS&T online store but they can be ordered by sending an e-mail to Customer Service.
A pdf of the scanned article is freely available from the Rochester Institute of Technology Web site (Copy/Paste this link:
https://home.cis.rit.edu/~cnspci/references/mccamy1976.pdf ).
Below, on the upper-left, is a photograph of Mr. McCamy with the ColorChecker during a visit at the Munsell Color Science Laboratory, in 2002.
In previous versions of this Web page, I challenged readers to try to improve it. This is a tricky image to correct; it is a JPEG made under
fluorescent lights which was somewhat auto-corrected in the camera. Three reader submissions are shown in the other images.
As of 2021, the ColorChecker is manufactured by the Munsell Color Company, a division of X-Rite, and sold by Calibrite. Here is a timeline of
how Macbeth, Munsell, X-Rite, and ColorChecker are related (source for 1915-2006 data: Macbeth Lighting History):
•
1915: Macbeth Artificial Daylight Company founded (New York, USA) (manufacturer of daylight fixtures)
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1918: Munsell Color Company founded (Boston, USA) (manufacturer of color standards based on the Munsell system)
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1965: Kollmorgen Instruments Corporation and Macbeth merge
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1970: Kollmorgen acquires the Munsell Color Company
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1976: ColorChecker developed by McCamy and al. at Macbeth, a Division of Kollmorgen
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1997: The Gretag Color Control System Division of Gretag AG ((Switzerland) merges with Macbeth
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2001: Gretag-Macbeth becomes Amazys Holdings AG (Switzerland)
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2006: X-Rite (USA) acquires Amazys Holding AG
•
2012: Danaher (USA) acquires X-Rite (Note: Danaher purchased Kollmorgen a few years ago).
•
2021: X-Rite divest the ColorChecker brand and products associated with the ColorChecker color target to Calibrite. X-RIte remains a
close partner to Calibrite and will manufacture the devices for monitor and printer calibration and provide color materials from the
Munsell Color Company for ColorChecker targets.
The ColorChecker consists of a series of six gray patches, plus typical additive (Red-Green-Blue) and subtractive (Cyan-Magenta-Yellow)
primaries, plus other "natural" colors such as light and dark skin, sky-blue, foliage, etc. The color pigments were selected for optimum color
constancy when comparing pictures of the chart with pictures of the natural colors... as reproduced on color film! Optimizing the human visual
match was thus not the first priority; still, it was shown, by the chart designers, that the degree of metamerism was also very small when
directly comparing the chart to the natural colors. Expressed otherwise, the perceived colors of the ColorChecker vary in the same way as the
natural colors they represent when the light source changes*, either when imaged on film or compared directly.
* Note: The technical term for a change in a single perceived color with various illuminants is Color Inconstancy, which is related to, but not the
same as, metamerism, the term used when two colors matching under one illuminant do not match under another illuminant.
Traditionally seen in photography magazines, in articles dealing with color film rendition, the chart has found a renewed interest with the
advent of digital cameras. In view of what was mentioned above relative to the ColorChecker being optimized for film based reproduction, it
could be argued that this optimization would not be ideal for the sensors of these new cameras. However, because the imaging sub-systems
of all digital cameras are specifically designed to mimic the response of the human visual system, there is no major reason why the
ColorChecker's natural color patches should not be trusted as valid substitutes for their natural counterparts in various lighting conditions**.
And what about the other non-natural colors, the additive and subtractive primaries, and the gray scale patches, which are not designed to be
equivalent to a particular real-life color? They were valid then, and they still are. In reality, the patches of a color chart do not need to be
surrogates of natural objects to make them useful, but the fact that some of the ColorChecker patches can be used in such a way is a definite
plus.
** Note: It would nonetheless be interesting to see an updated study on how images of the patches and images of the natural objects they
represent match when captured with digital cameras under various lighting conditions. It is important to mention that the match in the
preceding sentence does not imply that the images are accurate representations of the original objects, but that the colors of the patches and
the natural objects "change in the same way".
As many of us know, the various brands of digital cameras are like film; each has its own color rendering characteristics, which is constantly
modified by automatic white balance software within the camera. Basically, the accuracy of the colors at the output is a moving target. The
problem is such that many high end cameras provide a way to get the "raw" measurements extracted from the camera sensor, without any
processing; the file format is not surprisingly called "RAW" (RAW as in non-gamma-corrected, non-color-corrected, high resolution - much
more than 3 x 8-bit RGB - data from the camera sensor). The user can then manipulate the data and try to extract accurate color information
over a wide dynamic range. Where we just had to take the picture and let the photo finisher color balance our print, we now have to process
the colors ourselves; such is progress....
One way of helping the process of obtaining color fidelity is to use the ColorChecker as a target within the scene. Other charts with more
patches have been devised, the ColorChecker Digital SG first comes to mind, but this simple chart satisfies the needs of many since you can
make a rapid judgment by just looking at it. To illustrate how much we "know" this chart, here are four targets with the first three being only
different layouts of the original ColorChecker, and the fourth one, a representation of... the Datacolor SpyderCHECKR, a direct competitor of
the ColorChecker Passport, also with dedicated software, but manufactured in a larger format.
1
2
3
4
The first target shows patches sorted in a* (the a* of L*a*b*, from green to red, and from top to bottom, then left to right); the second one is
the usual ColorChecker layout, and the third one shows patches sorted in hue (the h of L*C*h). The first and third layouts do not look as
familiar, but you may hesitate a moment when looking at the last target on the right which has very similar colors and slight layout changes in
the first and third rows (Note: The third patch of the first row looks brownish in some Datacolor images (the User’s guide for example), and
greenish in others; the colors used for this image are the reference sRGB colors from Datacolor).
ColorChecker charts formats
For many years, the ColorChecker was available only in two formats: a "standard" chart approximately "letter size" (the standard North-
American writing paper size), and a smaller format about the size of a business card, called "Mini". These two formats are now called "Classic".
In addition we can now find the ColorChecker in other sizes or with additional patches for specialized applications. Here is a short description
of the formats which is followed by images of the charts. The thumbnails are shown with proper relative size. Click on the images to see larger
versions. The larger images are all defined at 96 dpi at the same scale.
•
ColorChecker (1976) and ColorChecker Classic
8 x 11 7/16 in. (20.4 x 29.0 cm) / purchased separately / Part #: MSCCC
The original chart, developed in 1976. While slightly larger when it was first made available, you can look at the chart that holds Mr.
McCamy in the image above for an example, the ColorChecker has remained pretty much the same over the last 14+ years. Of course,
the company name appearing on the chart, the branding, was modified as the Munsell Company changed hands (see here for a brief
company history); a few examples of these different versions are shown below. "Classic" is now added to the chart name to differentiate
it from the ColorChecker Passport and ColorChecker Proof. The edition/manufacturing date is usually printed in the back of the target.
•
ColorChecker Proof (2011)
4.5 x 6.375 in. (11.4 x 16.1 cm) / bundled with i1Publish and i1Pro solutions / Part #: none specific
A mid-size ColorChecker with openings in each patch whose purpose is to evaluate, to proof, the accuracy of custom-printed targets,
and thus the accuracy of a printing chain. The ColorChecker Proof cannot be purchased separately; it is provided uniquely in some X-
Rite "solutions", bundled with software (i1Publish, first available in 2011, which includes i1Profiler) or with software and hardware (ex.:
i1Photo Pro 2). The current charts have circular openings in the center of each patch; triangular openings were seen in beta versions of
i1Publish.
•
ColorChecker Passport (2009)
2.5 x 4.5 in. (6.4 x 10.8 cm) / purchased separately / Part #: Passport: MSCCPP; ColorChecker within the Passport: MSCCPPCCxxxx
Issued in 2009, this product replaces and enhances the original ColorChecker mini. The ColorChecker Passport has three targets: a mini
ColorChecker, a large light-grey target for white balance, and a target with patches designed to neutralize or enhance global color shifts
in images and other patches to control highlights and shadow clipping (this last target's use is maximized in a Raw workflow). The
ColorChecker Passport also includes software to generate DNG Camera profiles from images of the ColorChecker; the software is
available as a separate application or as an Adobe Lightroom plug-in. The ColorChecker target of the Passport, embedded in one of the
Passport pages, is the same size as the Classic Mini and slightly larger than the original Mini. The ColorChecker in the Passport has a
dedicated part number (MSCCPPCC); this part number is followed by what looks like an issue/manufacturing date: MMYY.
X-Rite
•
ColorChecker Passport Photo 2 (2019)
2.5 x 4.5 in. (6.4 x 10.8 cm) / purchased separately / Part #: Passport: MSCCPP-B; ColorChecker within the Passport: MSCCPPCCxxxx
Issued in 2019, this product replaces the 2009 ColorChecker Passport. The ColorChecker Passport Photo 2 adds an 18% grey target to
the three targets of the first version. This target comes with new software to create DNG or ICC camera profiles (the software also
supports the ColorChecker Classic and the Digital SG targets). It is interesting to note that while it was commercialized in 2019, most of
the targets used for promotional purposes and by reviewers indicate a 2017 manufacturing year (but not this review made with a 2019
edition). ColorChecker collectors will certainly want to add a 2017 pre-release target to their collection!
•
ColorChecker Classic Mini (2011)
2.5 x 4.5 in. (6.4 x 10.8 cm) / bundled with i1Publish and i1Pro solutions / Part #: none specific
A mini ColorChecker, identical in size to the one in the ColorChecker Passport. The ColorChecker Classic mini cannot be purchased
separately; it is provided in some X-Rite "solutions", where it is bundled with software (i1Publish, first available in 2011, which includes
i1Profiler) or with software and hardware (ex.: i1Photo Pro 2). As with the full size chart, "Classic" is now added to the chart name to
differentiate it from the ColorChecker Passport and ColorChecker Proof.
X-Rite
i1Publish/2011-01
•
Mini ColorChecker (original) (DISCONTINUED 2011-01-01)
2.25 x 3.25 in. (5.7 x 8.25 cm) / purchased separately / Part #: M50111
A miniature version of the original chart, designed for portability, which can fit in most camera bags. This chart was sold individually but
is now discontinued. It has been replaced by the slightly larger ColorChecker Passport, which also includes other targets and software. A
mini ColorChecker, identical in size to the one in the ColorChecker Passport, is also provided in some X-Rite "solutions", where it is
bundled with software (i1Publish, first available in 2011, which includes i1Profiler) or with software and hardware (ex.: i1Photo Pro 2).
brand unknown
X-Rite w/sleeve
date unknown
date unknown
•
ColorChecker Digital SG (NOT COMPATIBLE)
8 x 11 7/16 in. (20.4 x 29.0 cm) / purchased separately / Part #: MSDCCSG
Dedicated to digital photography, the ColorChecker Digital SG has 140 patches. 24 of the chart patches have colors similar to the
original ColorChecker and are laid out in the same configuration. The 44 patches on the periphery of the target are a pattern of three
neutral patches (white, grey, and black); these patches are designed to evaluate the uniformity of the Illuminance and the light Color
Temperature over the target. Fourteen patches were specifically selected to simulate the appearance of various skin shades (in addition
to the two of the original ColorChecker), and many patches of saturated colors were added to extend the color gamut in order to better
match the sensors of digital cameras. However, because of its Semi-Gloss finish, the SG in the chart name, the chart colors are not the
same as in the other ColorCheckers (more info); thus, DO NOT USE the Classic ColorChecker data for the patches of this chart.
gretagmacbeth
Circa 2006 ed.
New color specifications since November 2014
On October 23rd, 2015, X-Rite announced that new color formulations were required for the ColorChecker Classic and ColorChecker SG.
These changes affect the charts manufactured since November 2014. Regulatory and compliance reasons are invoked, so the changes
were likely due to the toxicity of pigments used in previous charts incarnations and to stricter environmental laws in some jurisdictions.
While X-Rite refers to the change as "BEFORE November 2014" and "AFTER November 2014", comments in the reference files indicate that
the November production was also made with the new formulations. The "BEFORE November 2014" data provided by X-Rite is the same
L*a*b* data used for comparison with our average of 30 charts; this data was first made available in 2005. Many patches in the "AFTER
November 2014" data are significantly different (i.e. there is a visible difference). Both old and new X-Rite reference files are provided in the
data section of the second ColorChecker page, where you will also find visual comparisons of the "Before" and "After" X-Rite data compared
with the BabelColor average of 30 charts, and synthetic images of the ColorChecker in L*a*b* and three RGB spaces.
Please note that our current average data corresponds to charts produced before November 2014. At the moment, we have measurements of
only a few charts produced with the new color formulations and we cannot provide statistical data. If you are interested in providing data for
the new formulations, please read the section (on the second ColorChecker page) that describes how to measure and format the data.
Source: X-Rite announcement
Where to buy?
Before the Internet, it was quite difficult to find where to buy the chart. With the wide spread of the Web plus the renewed interest due to
digital cameras, it can be found at many places. We used to provide a list of a few dealers but it is now easier to locate a supplier with the
following options:
•
The "Dealer Locator" on the X-Rite Web site
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Do a Google search with the following keywords: ColorChecker purchase
•
Look in eBay with this keyword: ColorChecker
GretagMacbeth
gretagmacbeth
X-Rite
October 1998 ed.
April 2006 ed.
January 2010 ed.
X-Rite/Triangles-beta
X-Rite/Circles-beta
X-Rite/Circles
Circa 2010
Circa 2010
i1Publish/2011-01
New ColorChecker specifications for
charts manufactured AFTER
November 2014 !
ColorChecker (1976-2024)
48th Anniversary !
ColorChecker pages revision history
•
April 2022: Several URL links required changes following the divesture by X-Rite of the ColorChecker brand and products to
Calibrite in 2021.
•
January 2016: Content separated in three pages. Data and image files were added for the color formulations changes done
by X-Rite in November 2014 and published in October 2015.
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April 2012: Complete Web page update and new content. Average data (Excel file) from 30 charts and updated images.
eciRGB_v2 data is now computed instead of eciRGB Version-1 data. We have added descriptions and images of the various
ColorChecker charts formats (Classic, Proof, Passport, Mini).
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April 2009: Added a file in CxF2 (CxF Version-2) format which contains both the averaged data and the X-Rite reference.
•
March 2007: Added visual comparisons between measured data and the average chart.
•
June 2006: Average data from 20 charts and updated images (now also in 16-bit format). The "RGB coordinates of the
ColorChecker" PDF was updated and augmented; it now presents a detailed comparative analysis of the latest (2005)
reference data, provided by GretagMacbeth, against the results derived from our spectral average.