Trade Tattoo went even further than Rainbow Dance in its experimental use of the three-colour process. This time Lye used the Technicolor system. The film is based on black and white “found footage” taken from GPO Film Unit documentaries (including Night Mail). The way he transformed these images has been described as the most complex job of film printing and colour grading ever attempted. He added animated words and patterns to make the images incredibly rich and multi-layered. Music was provided by a Cuban group, the Lecuona Band. The GPO sponsored the film as publicity for the idea of “posting early”.