Flow-On is a documentary about the early history of the window tinting industry. Originally developed as part of the war effort during WW2, "liquid tint" was formulated to block the U.V. rays in order to protect the eyes of aerial gunners and fighter pilots. After the war the formula was given to private industry where it was sold as an after market product. The method used for tinting windows during the 1950's and 60's was called the "flow-on" process. A variety of these colorful tints came in liquid form and was applied using a "flow-coating" machine.