Cokin filters were invented by professional photographer Jean Coquin. By using square filters like Cokin's, which fit into a holder and are attached to a lens via an adapter ring, the photographer has a number of immediate advantages. There is no need to duplicate filters to fit lenses of different sizes, up to three filters can be used at once to create unique effects, and the photographer has control over the positioning of the effect on the photograph.

• Adds warmth to image on overcast days
• Improves flesh tones
• Increases warm tones in autumn or desert scenes
• Allows image enhancement without changing the subject