> umm so the pigments have different reflective qualities that react to light > differently?
Short answer: Yes. Longer answer: most light sources emit light across a broad range of wavelengths. The reflectivity of a pigment varies with wavelength, so the amount of light reflected at any particular wavelength is the product of the amount of light the light source emits at that waveength and the reflectivity of the pigment. The final stage is the reduction, by the light sensor (in your eye, or on film, or on the CCD array of a *ist-D) to a single numeric value. Sensors, too, are sensitive to a range of wavelengths, and effectively sum (technically: convolve) all the effects of the illumination over the range of wavelengths they respond to. But the output from any one sensor is a single number; this may be from fairly dim illumination over a broad range of frequencies, a moderately bright light source at a single wavelength close to the peak response of the sensor, or from a very bright light source at a wavelength to which the sensor is not particularly sensitive. They all end up with the same single numeric value, so there's no way for the sensor to distinguish between them. A different sensor, with a slightly different response curve. may well come up with different values for all three of those cases. If one sensor is the human eye, and the other is your photographic capture medium, it's possible for colours which appear identical to one sensor to show up very differently on the other sensor. [I've only talked about one sensor; the argument extends to the three different colour sensors in the human eye, film, or CCD] Even more complicated answer: not all colour comes from surface reflectivity. Inkjet dyes (as opposed to pigments) work mainly as a transmissive medium; the light gets it's colour from passing through the dye, being reflected by the glossy white paper, and passing back through the dye, which absorbs some part of the light. The same sort of effects apply here as apply to reflected light. In the real world, even most reflected light has a transmissive component; the light penetrates some way into the pigment layer before being reflected, and pigments are usually distributed in a dispersal medium of some kind, which also affects the light. The transmissive attenuation usually yields a different colour from the absorption due to the pigment. This is one reason for colour shifts as the viewing angle goes from normal incidence to grazing incidence; you're seeing more of the transmissive effects, and less of the colour of the pigment.
