Projection Printing for Mural Graphics

1973- 1977

In 1973 and 1974 I received two faculty research grants (COFRS) from Florida State University to build a high intensity light source enlarger and to use it for direct projection of 4x5 negatives and positives. I learned color separation form negatives so that I could make color separations on 4x5 film. Using pigmented ammonium bichromate mixed with gelatin as a photosensitive emulsion, I would expose and develop each layer separately. I made the enlarger using a large lens and a bellows from an old speed graphic camera, for focusing on the emulsion layer. The exposure time using an 8 mm carbon arc light source was between 20 minutes on photo silk screens and up to 2 hours on 6x8 canvases. I used this device for several years, which made it inexpensive for me to produce very large work without contact printing orthochromatic film. The work that came from this process often consisted or 5 or more color separations since any colored pigment could be used in the emulsion. I also made double exposures on canvas to add new layers of information to the photograph. These large pieces are very colorfast and will outlast any normal photo process by centuries.