Wikipedia
An Orotone or gold tone is one of many types of photographic print which can be made from a negative. An orotone photograph is created by printing a positive on a glass plate precoated with a silver gelatin emulsion. Following exposure and development, the emulsion is coated with banana oil impregnated with gold colored pigment, to yield a gold-toned image. Alternatively, the developed glass plate can be gold-leafed by hand using 23 karat gold leaf. Being printed on glass, Orotone images are extremely fragile and often require specialized frames in order to prevent breakage. Other types of prints can be made with the same negative used to make an orotone. Consequently, silver gelatin prints and platinotypes (platinum, palladium) prints are also made by those who produce orotone prints.