Is it only in the eye that colors add up to be white? I've been thinking a lot about how electromagnetic waves work. The visible light is comprised of a electromagnetic radiation in the spectrum between 380 and 750 nm. Now, as far as I understand, if you "mix" all of these waves together, you get a color which the eye reads as white. What I'm wondering about, is if this "appearing white" effect is something that only occurs in the eye, or if it is some physical quantity. (badly formulated). Secondly, is white light actually all these different wavelengths "reacted" by constructively inteference? Thirdly, if so, I'm wondering what it would look like if you were to draw a sinusoidal graph for "white light". Is this possible? Thanks for any help!