You may want to double (or triple) pass to get the colors to POP with the light behind. Go to printer settings...check the box at the top and up the passes to 2 or 3. Do a sample test print and up the heat settings as you have more ink to dry. Oracal makes a great backlit film (Oracal 3850 I believe) and you can get the profile on their website for your specific printer, RIP, and Ink type.