Collotype

A photomechanically produced image made from a photographic image, with similarities to the lithographic printing process. The process evolved gradually from the work of A.L. Poitevin in the 1850s and is still in occasional use. It produces prints which can be of very high quality with finely detailed images and the appearance of having continuous tone. A finished collotype, especially if varnished, is often difficult to distinguish from a true photograph.