Are you talking about transparency films for printing positives and burning emulsion coated screens? Are you talking about emulsion films such as Ulano capillary direct and indirect films?
Printing film is simply color sep. your design and printing a positive in black for each sep on transparency film. You can purchase the films from any reputable Graphic supply house or high end print supply. You can also purchase film from screen print supply folks. The inks in your printer may determine the type film you purchase.
Printing Film 
