A photographic letterpress printing technique to mimeograph graphical templates. Pigment paper is covered with a layer of gelatin, then rendered light-sensitive in a potassium bichromate solution and exposed under a negative. The gelatin now becomes water-insoluble. The exposed pigment paper is developed in lukewarm water with the gelatin and the containing colour pigments being washed off the hardly and not exposed areas. A side-inverted positive is the result.