The Tiffen #4 Process Viewing Green Glass Filter is used for process photography. Balancing lighting with the eye is managed by experience. Decisions can be aided through the use of the contrast Viewing filter #4. It was designed to handicap the eye, with its much greater range of apparent densities, to resemble the range of various types of film. Using the Viewing Filter will help you judge relative highlight and shadow densities.
WARNING: This product may expose you to chemicals which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.