Most of the paint is not opaque enough to conceal the background color completely in thin layers. Your base coat can end up lighter or darker, colder or warmer, depending on what color it goes over. Orange flake going over lighter color looks lighter in tone than if I went directly over black plastic. Depending on how many layers you do, you can also see the background color reflecting through the top layers a bit. Like say you can layer metallic green over a shimmery gold color for a warmer tone. I find this to be more the case for metallic paints where the base color matters. But if you do enough coats, many paints are opaque enough regardless of the base color.
Anyway, I wanted to get a lighter orange, because my orange paint is a medium red-orange out of the can.
Important note: don't paint in high humidity! Paint will take a long time to dry and will interact with top coats. I have not been able to paint as well as usual in the past couple days due to rain and high humidity.
