Photographic filter
Videos
In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted
Four photographic filters (clockwise from top-left): an infrared hot mirror filter, a polarizing filter, and a UV filter. The larger filter is a polarizer for Cokin-style filter mounts.
Markings on Hoya multicoated skylight filter, identifying size and equivalent Wratten number (1A)
An extreme case: a Nikon D700 with a smashed filter which may have saved the Nikkor lens beneath. Usually, all that can reasonably be expected is protection from scratches, nicks and airborne contaminants.
Infrared filters
Color gel
Videos
A color gel or color filter, also known as lighting gel or simply gel, is a transparent colored material that is used in theater, event production, photography, videography and cinematography to color
Photographic filter
…used for eyeglasses (such as CR-39), polyester and polycarbonate; sometimes acetate is used. Historically, filters were often made from gelatin, and color gels. While some filters are still described as gelatin or gel filters, they are no longer actually made from gelatin but from one of the plastics mentioned…
Many color gels organized, some in gel heads
A motorized color gel