How does additive color mixing (RGB) on a monitor or LED light etc. simulate different wave lengths (frequencies) of light if it is just mixing different amplitudes of three discrete wave lengths?

Question

Having a background in sound I am probably coming at this all wrong but if you mix a 1kHz sine wave with a 2kHz sine wave at various amplitudes you will get various different sounding composite sounds but at no point will you be able to emulate say, a 1300Hz sound. How is it that mixing Red Light at 462 terahertz (or whatever) with green light at 545 terahertz (these are numbers I am just pulling off google) at the same amplitude can result in a perceived frequency equivalent to 516 terahertz or as we know it ‘yellow’?

Is it that the ‘yellow’ we experience from Additive colour mixing is not the ‘true’ yellow we see in the rainbow? Is it our eyes that make up the colour based on the input of two discrete light sources interfering with each other?

In: 10

Answer 1

It’s because the human eye only has red, green and blue colour receptors (or at least, we have receptors that are more sensitive in those areas) There is another one for luminosity eg- brightness, but we’ll stick with the colours for now.

Since we only really detect those three, all the screen needs to do is stimulate them in the same ratio as a natural colour would, and we get the same effect.