Rosco Roscolux Tough White Diffusion, 20" x 24" Sheet of Light Diffusing MaterialRosco's premier range of filters are manufactured in a unique technology to insure the longest possible life under hot theatrical lights. Three discrete layers are combined in 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. Diffusion filters are designed to alter the shadow characteristics or the beam shape of light.