The "whole" inside has been sprayed with white. You have to spray every thing inside so when its viewed from outside the colors seem all even. The white brightens the red and blue too. Painting from the inside makes everything work backwards. The white is more like the "base" coat. In order to seal acrylic paint you have to paint over it with clear polyurethane.
I use 2 or 3 light coats because the last thing I need is to have water eat my water based paint.....