If the camera and the lighting were theoretically perfect, what would be the RGB values of the six white to black squares on the MacBeth ColorChart? Assuming perfect color balance R=G=B.

Would they be: 255-204-153-102-51-000?

Thanks, Bill

-- Bill Watson (bwatson@mindspring.com), November 30, 1998

Answers

You're right that RGB values would be identical, for neutral color balance. As to the values themselves, that depends on the "gamma" the camera is set up to match. Unfortunately, there's no "right" answer here, since different computer systems use different gamma values. (This is why images that look fine on a Mac come out dark on a PC, and ones that look good on the PC look light on a Mac.) I once saw some "suggested" RGB values for the MacBeth chart, but couldn't locate them just now when I went looking on the web. We'll keep my eyes peeled, and will post something on our site if we can track this down. (Since the chart is produced by MacBeth, you'd expect to find something on the GretagMacbeth web site, but no luck there...)

-- Dave Etchells (web@imaging-resource.com), December 09, 1998.