Lighting diffusers using fluorescent lamps - lighting can be built into ceilings and overhangs by installing white translucent plexiglass sheet below fluorescent lamps. The plexiglass sheets rest on the projecting edges of the wood moldings or metal framing.Plexiglass sheet in 1/4" thickness is recommended for installations with areas larger than two square feet. For uniform diffusion of light, the distance from the plexiglass sheet to the fluorescent lamps should not be less than two-thirds of the distance between rows of lamps. All surfaces above the diffusing plexiglass sheets should be given at least two coats of high-reflectance white paint, with white enamel as a finish coat.
Lighting diffusers using incandescent light bulbs - When using plexiglass sheet in an incandescent lamp, you must provide sufficient space for ventilation between the light bulb and plexiglass sheet to prevent overheating and softening of the plexiglass sheet. For best results - even illumination and no hot spots - use show-case bulbs. The formula for determining the minimum distance between a given wattage bulb and plexiglass sheet:
Minimum Distance, bulb to plexiglass sheet = 1/2 the square root of the bulb's wattage.
