I am going to revive this one since it fits and I finally got some research done.
I get the feeling that a lot of people are going to be blending R_G_B colors this year my self included.
What I have found in the preview is that if two colors occupy the same pixel the values are halved and if third color is present the first two are halved again.
ie R(255,0,0) + G(0,255,0) = Y(127,127,0) is not yellow.
and worse {R(255,0,0) + G(0,255,0)} + B(0,0,255) =W(63,63,127) which is nowhere near white.
What I am asking is that the R-G-B components be added but each component is capped at 255.
so R(255,0,0) + G(0,255,0) = Y(255,255,0) true yellow
and R(255,0,0) + G(0,255,0) + B(0,0,255) =W(255,255,255)
and R(255,0,0) + G(0,255,0) + B(0,0,255) + W(255,255,255) = W(255,255,255)
A Picture of the present behavior and the desired behavior is attached.
Joel