> What are the CIE XYZ coordinates of each colored square?
In the most expensive versions, they measure each individual patch, in case printing imperfections make the colours slightly different. And of course because you can’t get the exact same inks when a product is 50 years old!
> How were the colors chosen?
Skin and foliage; primary colours; greyscale; and miscellaneous.
They also make a 140 colour patch version - the “ColorChecker Digital SG” - that provides more coverage; 14 different skin tones instead of 2 for example!
Not the exact same inks, for sure, but as a slight tangent—having grown up with RGB/YUV/CIE coordinates and Pantone swatches and process-color printing, but without painterly training, I’d long imagined the world of physical color reproduction to be largely continuous over the perceptible gamut.
In the spirit of the classic “Reality Has a Surprising Amount of Detail,” [0] I realized relatively late in life how finite and how discrete the set of colored substances—pigments, dyes, inks, reflective nanostructures—is. That, for example, ultramarine means ~the same thing today as it did in the lapis mines centuries ago, and so on. Frustrated, of course, by things like impurities and degradation at the hands of time and light and medium… but nevertheless finite sets of color-reflecting substances and applications at the bottom.
In my case, it was the Forbes Pigment Collection that got me started thinking about it:
And the strange notion of “new” colors, like YInMn Blue [1], and formulations, like Klein Blue [2] (to dwell just on ultramarine-style blues!)
…I still don’t have a firm enough handle on color in all its glorious complexity to have a real point: you’re right of course that even within tightly-controlled production processes anchored in chemical reality, things drift and it’s worth paying somebody to measure if it’s important to be right—I just thought I’d offer the notion as a Sunday morning treat, in the hope that somebody else found the rabbit hole as delightful as I did :)
Comments
> What are the CIE XYZ coordinates of each colored square?
In the most expensive versions, they measure each individual patch, in case printing imperfections make the colours slightly different. And of course because you can’t get the exact same inks when a product is 50 years old!
> How were the colors chosen?
Skin and foliage; primary colours; greyscale; and miscellaneous.
They also make a 140 colour patch version - the “ColorChecker Digital SG” - that provides more coverage; 14 different skin tones instead of 2 for example!
Not the exact same inks, for sure, but as a slight tangent—having grown up with RGB/YUV/CIE coordinates and Pantone swatches and process-color printing, but without painterly training, I’d long imagined the world of physical color reproduction to be largely continuous over the perceptible gamut.
In the spirit of the classic “Reality Has a Surprising Amount of Detail,” [0] I realized relatively late in life how finite and how discrete the set of colored substances—pigments, dyes, inks, reflective nanostructures—is. That, for example, ultramarine means ~the same thing today as it did in the lapis mines centuries ago, and so on. Frustrated, of course, by things like impurities and degradation at the hands of time and light and medium… but nevertheless finite sets of color-reflecting substances and applications at the bottom.
In my case, it was the Forbes Pigment Collection that got me started thinking about it:
https://harvardartmuseums.org/article/pigment-collection-col...
And the strange notion of “new” colors, like YInMn Blue [1], and formulations, like Klein Blue [2] (to dwell just on ultramarine-style blues!)
…I still don’t have a firm enough handle on color in all its glorious complexity to have a real point: you’re right of course that even within tightly-controlled production processes anchored in chemical reality, things drift and it’s worth paying somebody to measure if it’s important to be right—I just thought I’d offer the notion as a Sunday morning treat, in the hope that somebody else found the rabbit hole as delightful as I did :)
[0] https://johnsalvatier.org/blog/2017/reality-has-a-surprising...
[1] paper (PDF, open access): https://www.sciencedirect.com/science/article/pii/S259004982...
blurb: https://chemistry.oregonstate.edu/chemistry-news-events/yinm...
[2] https://www.centrepompidou.fr/en/pompidou-plus/magazine/arti...