Transparent or frosted plastic sheeting for diffusion and color correction — multilayer, heat-resistant, versatile. Foundation for gel frames and custom filters.
Polyester film is your workhorse in the lighting department—a multi-layered plastic sheet that you place in front of spotlights, HMIs, or even windows to diffuse, color, or correct light. Unlike cellulose acetate (the older generation), polyester can withstand significantly higher temperatures without deforming or yellowing. This makes the material robust enough for close-range applications and long shooting times.
In practice, you'll usually work with polyester film in two variants: transparent-clear (for fine diffusion without color loss) and frosted (with a roughened or ribbed surface for stronger light scattering). The thickness varies—thinner sheets are flexible and easy to stretch, while thicker variants withstand extreme heat radiation. You cut the film to size, stretch it in standard gel frames (60x60 cm, 120x120 cm), or create custom setups with plastic clips and duct tape. Advantage: The film can be layered—two or three layers for more intense effects, without tearing or steaming off like cheap fabric.
Color correction is a second major area of use. You combine polyester film with color filters (CTB for warm tone corrections, CTO for cool tone conversion) or create your own mixes—for example, for skin tone adjustments under mixed lighting conditions. Unlike glass filters, polyester saves you weight and the risk of breakage, and storage is uncomplicated. You also need polyester film for scan masks and color grade tests during editing or telecine work.
A few practical tips: Store polyester film flat and cool—direct sunlight causes deformation. When placing it in front of HMI lights, maintain at least 20 cm distance to avoid heat buildup. If the film starts to ripple, removal and re-stretching are your only option—repairing it isn't worthwhile. And: Polyester scratches easily; always pack your gel frames so the film faces inward when not in use. With clean handling and respect for temperature limits, polyester film is an investment that pays off over multiple productions.