Linear-space lighting is the single most important thing for
graphics programmers and technical artists to know. It’s not
that hard, but for whatever reason, no one really teaches it.
Personally, I got a BS and MS at Georgia Tech, took basically
every graphics class they had, and didn’t hear about it until I
learned about it from George Borshukov. This post is essentially
the short version from my talk at GDC this year. You can check
out the slides for more details. Here is the image I always
start out with. Hopefully your browser is not resizing it. The
left and right are alternating horizontal lines of white and
black. If you have a well-calibrated monitor, the middle-upper
square should be much darker, and the middle-bottom square
should be about the same intensity as the alternating lines. On
the left and right side, you get essentially half-way between 0
and 255. So the color that is half-way between should be
127/128, right? Nope. Actually, 187 is about half-way between 0
and 255. 128 is about much, muc