Cooler for a Developing Tray
Water-Jacketed Tray for Use in Cooling a Developing Tray with a Flow of Water
Regardless of the fact that tank development for photography is the better method under most conditions, there are many who take special delight in tray development, because they enjoy seeing the picture as it develops on the plate or film.
There are many of this class of photographers both among amateurs and professionals, and they universally experience much trouble in keeping the solutions cool enough for good work in hot weather or a warm dark room. Many schemes have been used, but there is none simpler than that shown in the illustration. It is certainly better than letting the developing tray float in the bathtub, a common practice among amateurs who are compelled to use the bathroom as a dark room.
Any tinsmith can make a water-jacketed tray of zinc at a nominal price. If one expects to use it for developing films by hand, it should be made relatively deep, or at least shaped so that whatever method is used in manipulating the film will be suited to the size and shape of the tray. I had one made of zinc to accommodate an 8 by 10-in. plate and providing about ¹⁄₄-in. space all around the sides and bottom of the inner tray for the circulation of the water.
Two brass gas tips were soldered into the ends of the tray and a rubber tube was attached to one of them, as shown. By connecting this tray to the bathroom hydrant the developing solution can be kept as cool as desired without slopping water where it is not wanted.—Contributed by T. B. Lambert, Chicago, Ill.