Manufacturer and builder 1, 1884
The exceedingly delicate colored photographs on glass, says an engineering paper, which have come into fashion somewhat of late, are produced by fixing a paper photograph upon a cushion-shaped glass with transarent cement, and when it is dry rubbing away two-thirds of the thickness of the photograph with sand-paper. The thin film left is then rendered transparent by soaking in melted paraffin wax, after which transparent colors are applied, which appear softened down when looked at from the front. The background and heavier portions of the picture are then painted in body color upon the face of another cushion-shaped piece of glass, which is afterwards fixed behind the first one.
An improvement in this process has just been made by Mrs. Nelson Decker, daughter of the late C. F. Varley, F. R. S., and the first of the young members of his family to have produced a scientific novelty. She has just discovered that the second sheet of glass may be abolished, a better artistic effect produced, and the picture rendered more permanent by being protected from the action of the air and deleterious gases by being wholly embedded in paraffin. She does this by quickly dipping the photograph in paraffin a second time after the transparent colors have been applied, and painting the heavier colors upon the back of this second coat. A third layer of paraffin is then applied, and the background painted upon that; this third coat may be finally protected by yet another layer of paraffin. Some practive is necessary to acquire the knack of doing this efficiently. It must be done quickly enough not to re-melt previous layers, and the plate must, after each dipping, be quickly tilted on end in such a manner that the paraffin does not run into ridges and thickened lines, but forms an even coating.