Hacker News Reader

What I'm saying is that RGB(128,128,128) is not halfway between RGB(0,0,0) and RGB(255,255,255), in the same way that a 4.0 earthquake is not halfway between a 0.0 earthquake and an 8.0 earthquake.

The scale is non-linear.

As far as I can see, the only true linear space is frequency space --- aka "EM spectrum" space.

View on HN

I believe this is why a gamma transform is made at presentation time. But maybe what you're interested in is adding RGB tuples before presentation?

What he is trying to do is produce a simple relation between RGB values and EM frequencies; which is not possible. There is no simple relationship there, RGB values are only related to how we see light, how our eyes work, not to the EM spectrum.

I believe what you are looking for is the alpha channel--the fourth color component which specifies how to blend two values. It doesn't make sense to add RGB(0,0,0) and RGB(0.5,0.5,0.5). It does make sense to add RGBA(0,0,0,0) and RGBA(0.5,0.5,0.5,0.5).

Reply on news.ycombinator.com