Gels

The gels and filters are applied to theatrical or cinematographic lights to modify the characteristics of the projected light. They can be made of glass or plastic (polyester). Plastic jellies are sold in sheets or rolls to be cut according to the size of the frame.

They are divided into different types according to the purpose for which they are used. They can be colored (color correction) – that change the color of the light beam or correct the excess of a particular color on stage.
Conversions (or also light correction) are another type of gels – they change the color temperature of the light, cool it down or warm it up. They are among the most used. The most common cold conversions are number 201 (cold) and number 202 (half cold). The most common warm conversions are the number 204 (amber) and the number 205 (light amber).
There are also neutral gels that do not serve to change the color of the light, but to reduce its intensity.
There are also diffusers (“frost gels”) which serve to diffuse the light, to make it more homogeneous and free of sharp variations, or to transform a direct light into a diffused light.

The filters are not only used in theatrical and cinematographic lighting, but also in architecture, concerts, television and in photography.