Another quick addition, since I didn't see anyone mention it. Melanin is the pigment that produces the black color on an animal. So an albino or amelanistic has no black on it at all, and a hypomelanistic (hypo for short) has reduced black, resulting in a greyed out or ghostly appearance when added to an otherwise normal BP.
EDIT: In some other combinations, hypo can tend to brighten the colors.
You may have already known this but I figured it didn't hurt to clarify.![]()