A color circle

[Chsavage]

I have a mind for the tedious. That being said. I would like to create a perfect color wheel, pixel by pixel, in photoshop. My question about this is simple. I've already created my transparent work surface, and already placed a "perfect" Red Green and Blue at the appropriate intervals in the circle. But about creating the colors that are combinations of these colors I was wondering: Since a perfect red is 255R 0B 0G, and perfect blue is 255B 0R 0G, is perfect purple 127R 127B 0G or is it 255R 255B 0G? I'm really excited about this protect because I have another project in mind that I'm going to use this for, so expect more questions!

 

[Tom Mann]

Take a look at this article:
http://en.m.wikipedia.org/wiki/Lightness

A color circle is nothing more than a planar cut through one of those clindrical diagrams at a constant value of perceived luminance, and with the saturation maxed out at 100%.

So, to answer your specific question, if we use the simplest model for perceived luminance, ie 0.33*R +0.33*G+0.33*B, your perfect purple would not be 256,0,256 because this would have 2x the perceived luminance of any of the pure primary colors ( ie, 256/3). I will leave it to you to work out whether 128,0,128 is too bright, perfect, or too dim, and/or exactly what the correct values should be.

Tom

 

[Chsavage]

Perfect article, now I've got some math to look out to do what I need, thank you!