Photographic Exposure

Developing Film

Exposed film contains a latent image that must be chemically developed. The manufacturers of film and chemicals publish charts of times and temperatures for use of their products. This lesson does not attempt to duplicate that information. Always read the manufacturer's recommendations and use them as your starting point.

Equipment needed:

Film can be developed in small tanks, deep tanks or trays. The average person beginning to process their own film will be using 35mm or 120 roll film and will opt for small daylight tanks. They are called "daylight" tanks because once the film is loaded and the lid is on the processing can be completed in daylight. The tanks for roll film hold the film on reels which spiral the film out from the center with even spacing between the surfaces. The primary types are stainless steel and plastic. The stainless steel tanks and reels are very durable and easy to clean. I find that my beginning students have some difficulty learning to load the film on the steel reels. Loading the film requires that you curl the film toward the emulsion side, push the end under a spring clip in the center of the reel, then carefully wind the film into the coils that hold the edges. It is necessary to hold the curl just tight enough to slip between the reel's coils and not pull the film, but rather just allow it to pop between the coils as you wind the reel with your other hand. I always have my beginning students do this several times with waste film, first in the light , then in the dark before they attempt an exposed roll.

Because the steel reels require considerable dexterity and practice you may prefer the plastic tanks and reels which have a mechanism for ratcheting the film into the reel. One side of the reel is free to twist part of a turn on the center post. With this type the film is simply inserted into the openings on the outer ends of the spirals until it is caught by a spring clamp, then the free side of the reel is turned back and forth on the center post while the film is pulled into the coils by the spring clamps. Many people find this easier than the steel reels.

Deep tanks are primarily used by volume processors. They are tall narrow tanks which hold several gallons of chemical and are deep enough to accommodate the length of a roll of film. A weight is clamped to one end of the roll of film and a hook to the other, then the film is suspended from a rod across the top. The quantity of chemical needed makes deep tanks impractical for the average amateur.

Trays can be used successfully to develop roll film but they require that all processing be carried out in the dark. To process using trays set up the trays so that you know exactly where each of the chemicals is then turn out the lights. Remove the film from it's canister (35mm) or paper backing (120 - 220) then "seesaw" the film through the chemicals by raising and lowering the ends alternately to keep the bottom of the loop in the chemical. To time the process you will need an assistant outside the darkroom calling the times to you or you will need to have prepared an audio tape with the appropriate times that you can play back in the darkroom.

In addition to the tank or trays, you will need: a thermometer, one or more measuring cups of laboratory graduates, a means of timing the steps, and some clips to hang the film while it dries. A quart size Pyrex measure cup from the kitchenware department will do and spring clothespins will do to hang the film. Be sure to arrange a place to dry it beforehand. Trying to do it with a wet roll of film hanging from one hand isn't efficient. For timing a large clock with a sweep second hand, a kitchen timer or a tape recorder will do. You need to record the tape with queues to start and end each step and intervals for agitation. If you do not have a totally dark room or closet to load the film into your tank you will also need a changing bag.

The Process:

Development - The first step in processing (after you've put the film in the tank of course) is the developer. Some photographers like to use a plain water bath first because it helps to evenly wet the film. With some of the newer films this is not recommended and may degrade the quality of your negatives. Check the manufacturer's recommendations before using a water bath as the first step. Pour the developer into the tank as quickly as possible then rap the tank sharply on the counter 2 or 3 times. This will dislodge any air bubbles that may be on the surface of the film.

Agitation is an important part of processing because the chemical in contact with the emulsion becomes exhausted as it works and it is necessary to exchange it with fresh chemical to continue the processing evenly. Kodak and Ilford have different recommendations for agitation timing and intervals but either will work. Kodak's recommendation is to agitate continuously for the first 30 seconds then 5 seconds each half minute thereafter. Ilford recommends agitating at one minute intervals with 5 inversions of the tank over ten seconds. I recommend that beginners use the method that the manufacturer used to establish their time and temperature charts for their film.

Stop/Rinse - After completion of the development you can use a commercial stop bath (such as Kodak Indicator Sop Bath) or a water rinse. My own method is a water rinse. Whichever you use try to have it close to the same temperature as the developer. Drastic changes in temperature can cause damage to the softened emulsion. The purpose of the stop/rinse is to stop the development and to remove (water rinse) or neutralize (stop bath) the remaining developer on the film. After dumping the developer, fill the tank with fresh water and dump it twice .

Fix - The next step is the fixer. It stabilizes the image and removes the undeveloped silver and the anti halation layer. Use the time recommended on the fixer you buy. If you were to remove the film from the tank before the fixing is complete you would find that the shadow areas are not transparent. Should you accidentally remove the film from the fixer too soon and see areas of opacity, put it back in the fixer until it has all been cleared for as many minutes as it took to make it clear.

Wash - The final step is the wash. It is necessary to remove all residual chemicals or the remaining traces will stain the negative over time. There are several methods available:

Water bath - with the lid off the tank and the film still on the reel, fill the tank above the reel with water and agitate by turning the reel with your finger. Change the water every 5 minutes and repeat for a total of at least 30 minutes (check the instructions on your film, some recommend as much as an hour).
Running water - this can vary depending on your equipment. If you use the tank you developed in and just place it under a gently running tap, you should wash for 30 minutes. There are some film washers designed to maximize the cleaning action of the flowing water which will clean the film in as little as 3-5 minutes.
Hypo clearing agent - there are several brands of chemical on the market which will neutralize and remove the fixer with very brief wash periods (30 sec. to 2 minutes) before and after the clearing bath which is usually 1-2 minutes.

Photoflo - An optional but valuable additional step is to treat the film in Photoflo (a Kodak product) before hanging it to dry. Photoflo is an emulsifier (it makes water wetter) and causes the water on the film to run off in a sheet rather than forming drops which can leave spots on the film. There are squeegee tongs (rubber blades on both sides facing in) to remove the surface water but I find they work best with Photoflo'd film and the tongs wetted with Photoflo. The rubber blades can scratch the emulsion if used carelessly or with the blades completely dry.

Dry - Hang your film in a dust free location to dry. You can buy special film clips for this. Some sets come with one clip weighted for the bottom end. Ordinary spring clothespins work fine.

Things to Consider

Stock solution vs diluted: Developer can be used as a stock (concentrated) solution and replenished with a replenisher solution, or the development time can be extended with repeated use. This is an economical method for those who do volume processing. The strong concentration also results in short development times. Again this is an advantage to those who process a lot of film. Many photographers however (including myself) prefer to use diluted developers as one shot solutions. Some developers, such as Ilford's Ilfosol-S and AGFA's Rodinal, are designed expressly for use as one shot developers. By not reusing developer, you are freed from having to track usage and calculate replenishment. That can be a nuisance, but the major reason for using dilute solution is that the longer development times result in more even development and better shadow detail. The lessened risk of uneven development is because slight variance in the length of a longer development time has proportionally less effect than with a short development time. The better shadow detail results from the fact that the highlights develop quickly and stop when fully developed. The shadow areas develop more slowly and benefit from the longer development as long as you diligently agitate to keep fresh chemical in contact with the film. Bruce Barnbaum in his book The Art of Photography discusses extreme dilution of Rodinal (1:150) as a one of his working methods. Such departures from the manufacturer's recommendations require considerable personal experimentation.

Contrast adjustment: A "normal" development time can be lengthened or reduced to alter the contrast of the negative. Such methods are usually reserved for sheet film which can be segregated into groups for shortened, normal and extended development depending on the lighting conditions in the subject. If you shot an entire roll of film under the same light conditions you might opt to alter the development for those conditions. Refer to books on the Zone system to learn specific methods for doing this.

Different developer = different results: The developer you use can vary the results you get. Some developers maximize the speed (sensitivity) of the film while others may produce sharper or softer images. Refer to the manufacturer's recommendations for specific films and developers to determine the best film/developer combination for the results you want. Ilford gives very complete recommendations in the technical data for their films including recommendations for times using their competitor's products in conjunction with Ilford products.

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