Making the Gumoil Print

Karl Koenig invented the Gumoil alternative process. He uses an enlarged interpositive to create a photographic image. The interpositive is contact printed onto paper hand-coated with a mixture of liquid gum arabic and potassium bichromate. This is exposed to an ultraviolet light source, then developed in water. The resulting image is then coated with oil paint, allowed to “set“; the excess oil paint is rubbed off with paper toweling, then the image is etched in a dilute mixture of water and household bleac