Anthony Barreiro wrote:I've been thinking about the question of creating colors by combining red, green, and blue light. Is this purely a technical issue for people who are creating digital images or television pictures, or is this analogous to what happens in nature? I think of the light that comes from the Sun or another star as having a continuous spectrum of all the colors of the rainbow, with interesting dark lines where specific wavelengths of light are absorbed by elements or molecules in the star's cooler outer layers. An emission nebula or a reflection nebula would have a much narrower spectrum, but it would be centered on a specific wavelength corresponding to a specific color, right? Am I missing something?
Color theory is very complex. Consider just the simple fact that we may perceive identical colors created by a single narrow emission line or a rich mixture of wavelengths across the spectrum. Consider that we perceive a particular hue as different colors depending on intensity. The thing that distinguishes orange and brown, for example, is intensity, nothing else.
The sensors in our eyes don't correspond very closely with the red, green, and blue primaries of our monitors, nor with the cyan, magenta, and yellow of our subtractive color systems. So displayed colors, printed colors, and the colors we perceive all occupy different mathematical spaces. Converting between them is non-trivial (and there are many things that can't be converted perfectly- for instance, it is impossible to duplicate pure red in the standard additive system used by monitors using the CMY system of printing.
