diffusing screen

Fluorescent lamps should have a smooth diffusing screen that filters out ultraviolet (UV) rays.

A muffler for an engine may employ all manner of reversing baffles, diffusing screens, and serpentine pathways to redirect exhaust gases that don't contain chunks of lead traveling at supersonic speeds.

To produce these effects, the animators used different techniques, such as drybrush, airbrush, charcoal, grease pencil, backlit animation or, during shooting, the cameraman used multiple exposures with diffusing screens, filters or gels.