Hey guys if I wanted to do mixing paint I would get different results if I simply added the colors. Is there an easy way of simulating mixing paint.
For example:
Red + Green equals yellow which is fine. Now if were to add red + green+ blue than it would turn white, but if I mixed the paint it should turn out be brown.
You’re talking about additive vs. subtractive light. Light emitted from a computer screen is additive, and uses RGB. Light bouncing off a surface is subtractive, and uses RYB (and here R + G doesn’t equal Y–instead you get brown–rather B + Y = G). So you’d have to set up a different color system, and use that to simulate subtractive light.
–Eric
Yes, and you can use cyan/magenta/yellow for subtractive color (plus black for various reasons), and other combinations (there are r/y/b/g/k presses, etc.), but I was trying to keep it simple. 
–Eric
What you really need to do is build your own color model, not RGB but RBYKW (Red, Blue, Yellow, blacK and White) You would need to test out some color combinations and create some math to get it done. You could also consider using CMYK. There are plenty of math models for that around the web.
RBYKW would be real world paints. Red, Blue and Yellow make dark gray if properly mixed