According to the classic compositional 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 avoiding a blurred sky and an underexposed landscape. Cokin's gray graduated filters: The neutral, more or less dark gray of these filters compensates for bright lights. The sky is underexposed, making the landscape and architecture appear more vibrant in color and depth. They are essential in summer for shots by the sea or in the mountains.