Rubylith®brand masking films are "light safe" knife cut films coated onto a polyester backing sheet. These films can be cut manually or on a plotter to produce masks for film contacting and plate making and film positives for photographic stencil production.

Rubylith® is a red masking film, which is suited for use with orthochromatic films. Rubylith®is "safe" for use with camera speed darkroom films as well as indirect gelatin stencil films and diazo, diazo acrylic, or SBQ sensitized stencil films or emulsions. Rubylith® is primarily used in the camera and plate making operations for offset lithography, flexography, gravure, and screen processes where orthochromatic films and plates are used.