The Cinelux Lighting Filter, #385 Royal Blue (24" x 25' Roll) from Rosco is part of a series of filters created for motion picture and television productions where large lighting fixtures are employed to create effects. This filter is produced using a specialized technology that insures the longest possible life under hot theatrical lights. The filter is general mounted within a frame and placed in front of a light source to create the desired effect. The three discrete layers from which they are made are combined by a tri-extrusion process. By sealing the colored layer between two microscopically thin layers of clear film, dye migration is minimized and effective life is extended.