Part of the issue is that there are really two opposite concepts of color - that of light and that of pigment. What people remember from art class (or that "yellow and blue make green" commercial) is how pigments interact, but those with a scientific understanding of the nature of color think in terms of light. Black is the absence of light, but on paper black is sufficient presence of pigment to reflect no light. On one hand, it's the absence of color; on the other, it's the presence of all colors. The light perspective is a more fundamentally correct means of considering the concept, but the pigment perspective is for many professions far more useful. As a computer person, I see RGB monitors and CYMK printers regularly and as such work from both perspectives, but I think in terms of light. - ZM