The 5.65 x 5.65” Orange #21 Glass Filter from Tiffen is used for landscape and architectural photography on black and white film. Although originally intended for use with black and white film, this filter can also be used as a creative tool in color imaging. This orange #21 filter absorbs blue and blue greens and renders blue tones darker as in marine scenes.

The filter is manufactured using Tiffen’s ColorCore technology, a process that entails permanently laminating the filter material in between 2 pieces of optical glass that are ground flat to tolerances of a ten-thousandth of an inch, then mounting them in precision metal rings.