film? are you some kinda stalker taking pictures from your dome light? getting a little to crazy in there huh??
jk, you could put some accetate, just like many others have put over there ac control bulb... i dont know how bright/dark its going to be... try outside of the car with a similar blub in a fashlight and put the film in and see... but if you do a lot of map reading then i wouldnt cause the po are going to get you for illegal lighting, if you put red, or blue in your car