Monday, July 30, 2007
Bram's comments on the last article got me thinking about halftones. This is probably obvious to most people but it was news to me. Without good color profiles and calibrated monitors, you of course can't get predictable appearance. Things like sRGB will help the first but 99% of monitors are not calibrated. But with halftoning you can (assuming LCDs are well behaved about half tone patterns-- CRTs sure are not) get predictable greyscales. For example here are two images with a 25% and a 50% greyscale. (and RE the last article, not which is more of a middle grey). It just doesn't matter what your gamma is (assuming your black point is dark!) to predict what these greys are.
This basic idea is often used for gamma estimation-- the best example is Greg Ward's great gamma image.