The Graduated Twilight Resin Filter from Lee Filters fits the Cokin P holder andmeasures 3.3 x 4.7". Often it is necessary or desirable to balance the light intensity in one part of a scene with another. This is especially true in situations where you don't have total light control, as in bright contrasty landscapes. Sometimes it is also desirable to add color to part of the photograph. Lee Twilight filters are half-color, half-clear, with a medium-hard graduated transition for blending into the scene.