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ENLARGED NEGATIVES: THEORY & PRACTICE

Now that we have tightened up the exposing procedure, we should move on to processing our film. You can't do much worse than processing sheet film like you do paper, that is to say, in trays. Consistency is not possible. Film developers are not designed to live in trays and will oxidize in short order. Processing the first test strip in a tray weakens the solution to the extent that the next sheet processed will receive less development than the test. Using a processor like a Jobo is a wonderful luxury and has changed my life in the darkroom, but there is life before the Jobo. For many years I processed sheet film in color print processing drums which were rolled on a motor base. There are many of these devices in the used photo equipment market with drums that will handle film sizes up to 16X20 inches. Another inexpensive alternative is the BTZS sheet film tubes sold by Darkroom Innovations. Before we leave our discussion of the working environment we need to address the subject of safelights. This is definitely a case where less is better. All the films used have recommended safelight requirements, either dark red or light red for orthochromatic (blue sensitive) films to none for panchromatic emulsions. No matter what the safelight, if films are exposed to these lights long enough they will fog. Another danger is the safelight causing a sub threshold exposure to the film. This is an exposure that is just barely insufficient to initiate development but still causes electrochemical changes to the emulsion relative to its ability to react with the developer. If this film is exposed and developed, areas which would normally remain clear will show some density. This will not show up with traditional fog tests. The best safelight for film is no safelight. With this in mind it is wise to take a look at the LED displays used on digital timers, especially since they are in close proximity to the enlarging easel. If the timer has a dimmer switch turn it down so that it is barely visible and aim it away from the easel. If no dimmer, several layers of lithographers tape (the clear red stuff) is good insurance.