When taking colour photographs in bright sunlight, especially by the sea or in the mountains, ultra-violet rays and the brightness of the sky throw out the picture’s overall colour balance.
The Skylight “filters out” the excess bluish tone, improving the overall clarity of the photograph while helping to restore the film’s natural colour balance. It also keeps skin tones free of colour reflections from nearby objects such as tree shade.
Skylight filters are available in two strengths 1A and 1B, the latter being a slightly stronger pink colour.
Many photographers buy a skylight filter for each lens and leave them screwed on to protect the lenses’ front elements.
Skylight filters are available in round type that screw into the lens in ever size imaginable. They are also made by Cokin for the square filter system, and Hoyarex and the likes used to make them for their systems.
Links to buy
Hoyarex 011 Filter
Cokin A230