The Tiffen 4 x 5.65" Graduated Neutral Density (ND) ND 0.9 Filter enables the shooter to adjust exposure without affecting color balance. Neutral density filter is available in 1, 2, 3, or 4 stops to suit individual situations.
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 contrast landscapes. Exposing for the foreground will produce a washed-out, over-exposed sky while exposing for the sky will leave the foreground dark and under-exposed. This filter enables cloud detail to be kept correctly exposed in the picture.
Determining which graduated neutral density filter yields ideal results for any given lighting situation takes knowledge, experience and a collection of such filters. Choose the filter strength which adjusts the lighting to stay within the exposure latitude (greatest difference between bright/dark values) which still shows details in both of the digital or film medium in use. The Hard label indicates the degree of color graduation. The Vertical indicates the direction of the graduation.
Tiffen's ColorCore glass is produced through a process that entails permanently laminating the filter material in between two pieces of optical glass that are ground flat to tolerances of a ten-thousandth of an inch, then mounting them in precision aluminum rings.