Non-Linear color interpolation?

Question

If I have a straight line that mesures from 0 to 1, then I have colorA(255,0,0) at 0 on the line, then at 0.3 I have colorB(20,160,0) then at 1 on the line I have colorC(0,0

Answer 1

The correct way to interpolate RGB is to correct for gamma first, making the color components linear, perform an interpolation, and then convert back. Otherwise you will get errors due to the values being nonlinear. See http://www.4p8.com/eric.brasseur/gamma.html for more information (although the article is about scaling, scaling is usually done by interpolating pixel values).

If you have sRGB values, you can convert between linear and nonlinear using the formulas here: http://en.wikipedia.org/wiki/SRGB (use the Csrgb and Clinear formulas)

On the other hand, the errors are not huge, so it depends on your application if they matter.

For the interpolation itself, simple linear interpolation should suffice (as others here have noted). See http://en.wikipedia.org/wiki/Linear_interpolation for the specifics.