Every beginner tutorial I’ve seen so far does something like this:
Color of pixel = Color of material * (whatever BDRF and attenuation functions) * intensity of light
So let’s say I had a pure blue material, RGB: [0, 0, 255].
If I put a really intense white light next to it, the color of the pixel ends up being [0, 0, 255].
But in real life, I took a bright white light very close to a blue piece of paper. The paper appears white, not solid, bright blue.
Also, let’s say I have a pure red colored light RGB: [255, 0, 0], and I have a material that’s purely blue, as in RGB: [0, 0, 255].
I tried putting a red light next to a blue piece of paper. When the light is very close, the paper appears red. If I move the light a bit away, the paper actually appears purple (red + blue = purple, makes sense).
What kind of lighting model accounts for these kinds of phenomena?