Rubylith (original) (raw)

Rubylith is a brand of masking film, invented and trademarked by the . Today the brand has become genericized to the point that it has become synonymous with all coloured masking films. Rubylith consists of two films sandwiched together. The bottom layer is a clear polyester backing sheet; the top layer is a translucent, red-(ruby-)coloured, sheet. The top layer can be cut and peeled away from the bottom layer. The top layer's colour is light-safe for orthochromatic films (which are sensitive to blue and green light but insensitive to red light).