Cokin P172 VarioColor Pink/Orange is a colored light filter. It is used together with a polarizing filter to change the color in the toning range from pink to orange. Reflected light rays become polarized.
Polarizing filters are used to filter the light rays that enter your camera lens. They can remove unwanted reflections from non-metallic surfaces, such as water or glass, and saturate colors to provide the best contrast.
If you combine P172 VarioColor with a neutral polarizer P164 (or P160), you can change the color by rotating the neutral polarizer. For example, depending on the relative rotation of the pink-orange-hot filter P172 VarioColor and the neutral polarizer P164, the reflection acquires either a pink shade or an orange shade. The effect can be seen in the viewfinder and depends on how the filter is rotated and its orientation in relation to the sun.
These Cokin color filters can be used in conjunction with other Cokin P-series filters.