According to the classic composition rules of landscape photography, the sky occupies three-fifths of the height above a real or imagined horizon. This creates a significant light intensity between the lower and upper parts of the image, which balances out: thus, a blurred sky and underexposed landscape are avoided. The blue gradient filters from COKIN enhance the blue color of the sky and emphasize the colors of mountainous landscapes. They are also ideal for seascapes, as they highlight the white of the crashing waves.