RGB values of visible spectrum

Question

I need an algorithm or function to map each wavelength of visible range of spectrum to its equivalent RGB values. Is there any structural relation between the RGB System an

Answer 1

This is most of what color profiles deal with. Basically, for a given device (scanner, camera, monitor, printer, etc.) a color profile tells what actual colors of light will be produced by a specific set of inputs.

Also note that for most real devices, you only deal with a few discrete wavelengths of light, and intermediate colors are produced not by producing that wavelength directly, but by mixing varying amounts of the two neighboring wavelengths that are available. Given that we perceive color in the same way, that's not really a problem, but depending on why you care, it may be worth knowing anyway.

Without a color profile (or equivalent information) you lack the information necessary to map RGB value to colors. An RGB value of pure red will normally map to the reddest color that device is capable of producing/sensing (and likewise, pure blue to the bluest color, etc.) -- but that reddest or bluest can and will vary (widely) based on the device (and in some cases not just the device itself either--e.g., switching inks in a printer can change the characteristics).