I have found that using the Testors Transparent colors on the inside of the canopy work best for colors. It gives you a canopy that you can see through like your car and see the inside guages, pilots and other scale effects you might want to use inside. Some plastics won't take the Rit dye. Lexan is one of those type of plastics and that is what the U can Do s canopy is made of. So try the transparent paint and darken to the desired depth.