Semi-transparent material that diffuses light without preserving sharpness of objects behind it — diffusion paper, opal acrylic. Softens and scatters light evenly.
Translucent materials are your daily toolkit when you need to soften light without losing complete control. Unlike transparent surfaces – where you can still clearly see underlying structures – translucent material completely destroys this sharpness. The light is diffusely scattered, loses its direction, but is also noticeably weakened in the process. This is exactly what you need when a pinpoint lamp appears too harsh or when you have to improvise large, broad light sources.
In practice, you work with translucent materials such as diffusion paper (various densities: 1/4 stop to 2 stop light loss), opal acrylic sheets, or classic tracing paper. You stretch them directly in front of your lamp – between the light source and the subject – or use them as standalone diffusion walls in front of a window. The effect: shadows become soft, but modeling contrast is retained, and light is distributed evenly. This is different from bounce solutions, where you actively have to bounce light back.
Light loss is the trade-off you have to accept. A 2-stop diffusion halves your light quantity twice – meaning you need a stronger lamp or a longer exposure time. That's why you always check with a spotmeter on set first to see if the lux values are still sufficient. Rule of thumb: start with finer material (lower light loss) and then sharpen specifically. Conversely, becoming weaker is often expensive.
Translucency is clearly distinct from transparency (completely clear) and opacity (opaque). Some materials – such as high-quality diffusion gels – also function partially reflectively, giving you additional light reflections. You use this in practical lighting or when you need to illuminate large areas with few lamps. Try out the materials on location: the color tint also varies. Bluish diffusion paper appears colder, amber-tinted versions warm the tone.