In fact, for the purpose of this simplified discussion, we could say that one of three things, will occur at that point. Our light (or parts of it at least) will either be absorbed, reflected, or transmitted (that is, pass through) the object it is falling on. To use the technical parlance, we will see absorption, reflectance, and transmittance or maybe a combination of two or more of these occur. Exactly how these combinations work will depend entirely upon the physical properties of the material/object that the white light is striking.
Absorption: This is what happens when the substance from which an object is made holds onto or absorbs certain component wavelengths of the light striking it. In the case of a black or nearly black object for instance, pretty much all of the light wavelengths are being absorbed, and so what we are left with is (quite literally) an absence of diffuse light reflection. You will have probably noticed that many...