Why is it that black colors create a positive elctrical charge, while white colors send a negative charge? Does it have to do with different wave lengths? When light (in a copy machine) is focused on to the photoconductive drum, why and how does the black color become positively charged? I know that the ink that is applied is negatively charged, and through the priciple of opposite attraction, the ink is attracted to the colors (black or whatever, as long as it isn't white). But why can't the ink get negatively charged? The black colors are already positively charged. How do things get positively or negatively charged? I know its when an ionic bond takes place, and an atom has more electrons than protons, but how is this induced to occur? Why does this sort of reaction create a charge?