Equipment and Materials

by Gordon J. Holtslander Alternative process work can be accomplished without having a proper darkroom, but having one is a great advantage. The materials used in alternative process photography are not nearly as light sensitive as silver-gelatin materials. It is often possible to use a temporarily darkened room with success. Care must still be taken to not inadvertently fog material. The usual graduated cylinders and processing trays are necessary. It is very useful to have a small balance for weighing out materials. A lot of materials are available in kits, with individual compounds packaged in pre-weighed envelopes, making a balance optional for the beginner. Light Sources Most alternative processes are sensitive only to ultraviolet light. Most light sources used in silver-gelatin processes do not emit a significant amount of ultraviolet light and thus are not useful in alternative process work. It is necessary to have a light source that emits significant amounts of ultraviolet light. Common light sources of UV light are full spectrum or plant growth fluorescent lamps, sunlamps, Mercury Vapour lamps. The cheapest most accessible source of UV light is the sun. Using the sun is difficult because the amount of UV light that lands on a particular location is quite variable and unpredictable. This tends to make things even more complicated. Please see the article Using the Sun as an Ultra-violet Light Source for more information. A fluorescent printer can be made by creating a bank of small strip lamps to evenly illuminate a particular area. Wiring a bank of fluorescent lamps is quite simple -- most public libraries have books on this. The critical thing is to get an even illumination. It is helpful to have the lamps mounted on a spacer so they point down to the work surface. The print and contact frame can be slipped underneath the printer. This method eliminates a layer of glass, which absorbs UV light, and thus makes exposure times somewhat shorter. I've use what is known as a self-ballasting mercury vapour lamp. This is a MV lamp that screws into a normal incandescent light fixture. This is very easy to set up though the lamps can be a little expensive costing between $50 - $150. These should only be used for small prints 4x5 or smaller because the intensity of the light decreases from the center. Large prints would be given uneven exposure. A bank of MV lamps could be constructed for making large prints, however a flourescent system would likely be easier. Printing Frames Most alternative processes use contact printing. Contact printing is when the negative and support are tightly sandwiched together under glass. The negative must be in complete contact with the support in order to get a sharp image. A device for holding the negative and support together during exposure is necessary. The simplest method is to use a large piece of glass. The weight of the glass holds the negative and support in place. If you are planning on doing Gum bichromate printing with multiple prints some sort of registration apparatus must be used to allow for multiple exposures. Most photography stores carry contact printing frames. Some of the mail-order supply houses that cater to alternative processes carry contact printing frames made especially for alternative process work. Enlarged Negatives It is necessary to use a relatively large negative in alternative process work, because the work is contact printed. The resulting image is only as big as the negative used to make the print. Ideally original large format negatives are used. Original negatives have the greatest resolution and clarity. Large format negatives are made in large format cameras. Unfortunately not everyone works with large format cameras so an enlarged copy negative must be made. There are two ways to do this. A direct positive film can be used. The original negative is enlarged onto the direct positive film. The direct positive film is processed resulting in an enlarged negative. The other method is to make an interpositive. The original negative is enlarged or contact printed to normal film and processed, resulting in a positive. The positive is again enlarged or contact printed to regular film and processed giving a negative. The interpositive method allows for a great deal of control of the contrast and density of the final enlarged negative. This can be quite helpful because different processes often require different qualities of negatives. The low-tech way to make large format negatives is with a pinhole camera, though the resulting image has low resolution. This would be fine for gum-bichromate prints, but a real waste if used to make platinum prints.

Information provided by: http://duke.usask.ca/~holtsg/photo/faq.html#EQUIPMENT