The Formatt 4 x 4" Deep Green 61 Filter is used to control contrast in black and white film. This filter is predominantly used when a strong black and white contrast is desired.
Formatt, a company with three generations of professional filter-making experience produces every filter to the highest technical standards. The finest materials, together with state of-the-art production technology have resulted in a standard of optical excellence unmatched anywhere else.
Filters for black and white photography perform a variety of filtration effects including contrast control, enhanced skin tones, tonal corrections and more dramatic landscapes
Although originally intended for use with black and white film, this filter can also be used as a creative tool in color imaging
Absorbing Cell Technology
The secret to Formatt's consistency in filter design lies in its unique "Absorbing Cell Technology" (A.C.T.); this unique process allows color correct dyes to be applied to optically pure, wafer thin absorbing cells and offers a controllability that ensures the smoothest grad lines and consistent color across the whole filter surface.
This process is revolutionary compared with conventional filter dying techniques by eliminating the need to directly coat the glass surface itself; the repeatable performance gained through A.C.T. ensures that at any time you have to swap like filters for like filters mid shoot you can do so with confidence with no discernible differences in color or density.
Each filter is guaranteed flatness to a maximum 2-wave value and comes with an individual reading from a laser interferometer; every filter is carefully verified with a densitometer and spectrophotometer to ensure consistent and accurate transmission, before leaving the factory - the result is an absolute purity of image that eliminates any unwanted colorcast caused by conventional greenish soda-lime glass.