The Cokin Red filter is a favorite of landscape photographers because it turns a blue sky almost black and makes clouds pop out giving the scene an almost 3D effect. It also helps cut through haze and fog increasing detail and contrast. It really helps help increase definition between flowers and foliage. Green is rendered nearly black while yellows and reds are lightened creating better separation and contrast. Filter Dimensions 100mm x 100mm Filter Factor 8x (3-stop) Filter Construction C39 Optical Resin