Using the additive process (see Colour), created glass photographic covered with a mixture of minuscule starch grains that had been dyed red- orange, violet, and green, and finished with a layer of light-sensitive material. When put in the camera, bare glass side exposed to the light, the grains functioned as tiny filters After development into a unique direct positive image, and viewed in bright sunlight or with an artificial light source, the small glass plates glowed like coloured jewels.