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Process Times for Black and White Film (Starting Point)
- Rotation Speed (with reversing directions) 'P'/75 for 1500 and 2500 tanks, '4'/50 for 3000 drums
- Temperature 68°F (20°C)
- Pre-Rinse 5:00 Use same amount of water as the tank needs for the developer. Rotate on the processor for five minutes.
- Developer x:xx Use your normal time for hand inversion processing, or the film manufacturer's recommended time.
- Stop-Bath 1:00
- Fixer (rapid type) 5:00 Some film and fixer combinations require a longer fix time.
- Rinse 5:00 Use the same amount, or slightly more water than needed for developer. Change the rinse water every thirty seconds, and allow to rotate on the processor. A five minute rinse will be ten changes of water.
- Wetting Agent 1:00
- Dry As needed
Pre-Rinse
The tank and film are brought to process temperature. The emulsion is completely soaked with water.Developer
Exposed silver salt is converted to metallic silver. Density and contrast are determined in the developer.Stop-Bath
The stop-bath quickly and evenly ceases development. The emulsion is made acidic for the fixer.Fixer
The fixer removes the unconverted silver salt.Rinse
This rinse removes the fixer from the emulsion. Removal of the fixer is necessary for image permanence.Wetting Agent
Wetting agent is an optional step that helps film dry spot-free.Dry
As needed.
Black and white film processing is easily done in the CPA-2 and the CPP-2. Since there are many film and developer combinations, you must determine the times with black and white film processing. It is easy to have a starting point that will quickly lead to negatives with a full range of tones, and are a joy to print. If you are unfamiliar with black and white film processing use the procedure listed above. If you are already experienced with black and white film processing, and want to know about alternative procedures, see the 'Black & White Film Processing In-Depth' section for details.
The rinse of five minutes is sufficient to achieve a commercial level of fixer clearing. A ten minute rinse should be sufficient to clear fixer from the film to 'archival' standards. Some people may prefer to use an additional procedure to maximize the removal of fixer from the film. You may optionally include a Hypo Clearing Agent, Wash Aid, or other product specifically intended for this purpose. If you choose to use one of these products, follow their instructions for the times of each step and additional rinses (if any). These clearing chemistries may be safely used in the processor.
The type of negative desired in black and white varies with the film, your enlarger (condenser or diffusion type), the developer, and the desired print appearance.
For a condenser enlarger, you would normally desire a negative that is a little lower in contrast and density than one for a diffusion enlarger. The enlarger type will affect your developer choice and time.
If you are having prints made by a minilab ('One Hour' type lab), they usually print with machines that use diffusion enlarging equipment. Custom labs may offer both types of enlargement services. If you are unsure, ask the lab which type they provide.
A five minute pre-rinse of any black and white film works with the developer to produce a negative with manageable contrast and good tonal range, using the manufacturer's recommended 'hand process' (intermittent agitation) times. To pre-rinse, put a quantity of process temperature water in the tank, equal to, or slightly greater than, the amount of developer. Allow this loaded tank to rotate on the processor for five minutes. At the end of that period, pour out the pre-rinse water, and pour in the developer. Pre-Rinse times shorter than five minutes may produce irregular development, and should be avoided.
If you do not want to use a pre-rinse, you will need to determine the appropriate developer time for each specific situation. Rotary agitation affects different film and developer/dilution combinations to differing extents. Some developing times may be essentially the same, while others are significantly shortened or even extended. As a rough guide, try shortening the developer time by about 15%. This could vary by anywhere from about -25% to +10% from the original 'hand process' (intermittent agitation) times. A five minute 'pre-warm' is recommended when foregoing the pre-rinse. This time allows the film, reel(s), and tank to stabilize at the development temperature, before the developing begins.
The CPA-2 or CPP-2 can be used with chemicals manufactured by Kodak, Ilford, Agfa, and many others. JOBO also has a line of black and white chemicals made by Tetenal.
With these features in mind, let's set up a typical starting point for your favorite film and developer combination. If you have a developer time that has worked well for you with hand (inversion) processing, start with that time. If you do not have that time, look in the film or chemical manufacturer's information. Get the time they suggest for inversion (hand) processing. Set up your processor to work at 68° to 75°F (20°-24°C).
Some notes on the process:
You may have to experiment (test) to get the best negatives. To test, expose a roll of film. Use segments of that roll to process at various developing times to determine the developer time you want without great expenditures of film and time. Often the hand inversion time is very acceptable, and is an excellent starting point.
Keep your pre-rinse and rinse water at the same temperature as your water bath and chemicals.
Use the fixer time given by the chemical manufacturer, for the type of film you have chosen.
If you can't find a recommended fixing time for your fixer and film combination, use this procedure. Place a short length of film in a small container of fixer. Gently agitate the container. Time how long it takes for the film to turn clear. Use twice the time it took to clear as your fixing time.
For the final rinse, the number of changes of water is of more importance than the time. If you are going to complete the rinse in the processor, do a series of 30-second changes. Use a quantity of water slightly greater than the developer quantity for each of the changes. Pour in the water, allow to rotate for 30 seconds, dump, pour in fresh water, and repeat. The number of changes of water is ultimately more important than the timing of the rinse steps. If it takes you longer than 30 seconds to do a rinse cycle, be sure to do at least as many cycles as would be done if the rinse time were adhered to. For example, five minutes would require at least ten changes of water, even if it took longer than five minutes. Optionally, do several rinses on the processor, then remove the tank and use a constant flow rinse, with the JOBO Cascade Washer, #3350.
Hypo-clearing or hypo-eliminator products also may be used to reduce the rinse time required. Use the times and rinses recommended by the chemical manufacturer when using hypo-removing products.
Caution: Some black and white films are designed to be processed at temperatures between 20 and 24 degrees C (68 to 75 degrees F). If these black and white films are processed at a temperature beyond this range, it may damage or destroy the emulsion (images). Do not go higher or lower than the temperature range published for the specific film and developer combination. If you do process at extreme temperatures, be sure to follow the film and chemical manufacturer's instructions for special techniques and/or chemicals necessary to safely process your film.
Note:
It is good practice to be consistent in processing procedures. However, it may be useful to know that with the exception of the developer, all steps in the black and white film process are 'taken to completion.' That is, once the action of the chemical or rinse has done what it is supposed to (had its effect), further time in the bath or rinse will have no additional benefit or harm. If you are to err in the timing of the process steps other than the developer, it is safer to go longer, not shorter. Be aware however, that very long (over one hour) immersion times in any solution or water could cause excessive softening of the emulsion or other problems, and should be avoided. Fixer should not be used for more than twice the recommended time, as ultimately it will bleach the image.
Some comments on tanks and developers:
All JOBO tanks are labeled with the quantity of solution required to completely cover the film level in that tank on a rotary processor. If you process only one roll of film in a two reel tank, you still have to use the solution quantity specified for that tank. Any lower quantity will be too low to cover the film at the center of the reel. The solution quantity marked on the tank is the minimum quantity - the tank will hold more.
There are numerous black and white film developers on the market. Many different dilutions of these developers can be used. You must pay attention to the developer concentration and quantity of that specific dilution you plan to use. A specific area of film (square inches) will require a specific quantity of developer to process the film properly. If you use a more highly diluted developer, test to ensure the quantity of diluted developer used will properly develop your film. Not enough developer could cause underdevelopment. This type of underdevelopment cannot be compensated for by extending the developer time.
An example:
According to Kodak's instructions, 100 ml of Kodak D-76 stock solution will process one roll of 35 mm, 36 exposure film. A popular dilution of D-76 is to mix the stock solution 1:1 with water, and extend the development time. If you use the same quantity for the diluted developer as the original stock developer, the film will be underdeveloped. There is not enough active developer agent in the 1:1 solution to develop the film to the same density as the stock solution. When using a diluted developer, increase the quantity of the developer solution by at least 30%. The correct development time will be different with each dilution. Be sure to refer to the correct time (from the chemical manufacturer) for the dilution you are using.
You may find that extreme dilutions will require a reduced quantity of film in the tank. This reduction provides enough active developer to finish the development of the film. (An example is one roll of 35 mm film in a two reel tank.)
Maximum Volume:
Avoid volumes in excess of 1000 ml in a tank or drum. Using too high a quantity will ultimately damage the rotation mechanisms.
WARNING: It is possible to mount a tank, or tank and module combination on the processor that would require more than 1000 ml to properly cover the film contained inside. Although this tank would 'fit the processor,' doing so would strain the rotation motor, and should be avoided.
The 'inversion' quantity of chemicals marked on 1500 series tank labels is approximately the maximum amount of chemicals the tank will hold when processing with the magnet drive (or by hand).
The 2500 series tanks are not intended for inversion processing, and are not labeled with inversion quantities. To determine the maximum quantity for a 2500 series tank for use with magnet drive process, place an unloaded tank vertically and fill with water. Measure this volume of water and divide by two.
When using a JOBO Lift and any size tank, excess chemicals or water poured into the lift will immediately flow out the drain hose. Filling to overflow with water may be used with an unloaded tank, to determine the maximum volume of chemicals usable with the tank and lift combination. Drain, capture and measure the volume of water retained in the tank.
Push or pull processing (one or more F-stops) of black and white films should be considered a salvaging procedure to correct for incorrect exposure of the film. Under poor lighting conditions (or the lack of an appropriate speed film) it may be necessary to underexpose the film and 'correct' for the under- (or over-) exposure with adjustments in the processing.
The best quality processing will be derived from a combination of correct camera exposure and normal processing. The greater the push or pull, the more likely the results will be unsatisfactory. Use push or pull processing only when necessary to accommodate exposure deficiencies, or to exploit the 'artistic quality' (less realistic appearance) of the altered images.
The length of time in the developer determines the effective exposure index. Note that different films will have different 'normal' developer times, thus the modified developer times for pushing or pulling these films will be different also. All other process steps and times are unchanged.
The recommendations below are approximate. Some film/developer combinations may require more, or less change per stop. Tabular grain films specifically may require less adjustment. Try about half of the amount of percent of increase listed below for tabular grain films. If the film data sheet has differing recommendations, use them.
Changing the developing time causes a change in sensitivity in the following way:
- A 'Push' of one F-stop (2 x ASA) is obtained by a 30% increase in normal developer time.
- A 'Push' of two F-stops (4 x ASA) is obtained by an 80% increase in normal developer time.
- A 'Pull' of one F-stop can be compensated for by reducing the normal developing time by 30%.
Fractional F-stop push or pull developer times may be calculated by adding or subtracting 10% for 1/3 F-stop, 15% for 1/2 F-stop, and 20% for 2/3 F-stop. A fractional F-stop adjustment may be added or subtracted to the full F-stop(s) push or pull times as required.
Caution: The above processing information should not be used with Kodak Microdol-X or other silver solvent type developers. Silver solvent 'fine grain' type developers do not push well if at all. It is better to use a 'high energy' type developer for better push process results. If you are in doubt about the suitability of a developer for pushing, check with the manufacturer of the developer.
Caution: Any process which changes the effective exposure index (ASA) of the film may produce less than optimum images. Contrast and maximum density will be altered. The need for accuracy of the camera exposure necessary for a 'correct exposure' is increased. The 'correct' exposure for a push process may need to be a compromise, sacrificing shadow detail for highlight, or vice versa. Higher levels of contrast in the lighting during exposure may make it impossible to render all portions of the picture (darkest to lightest) with a distinct image. Highlight details could 'block up' and/or shadow details could lack density and discernible content. The apparent 'grain' structure of the images will be enlarged. With any pull process, contrast is decreased. The apparent 'grain' structure of the images will not be reduced.
Since there can be tonal shifts and contrast changes when using different developer times, we recommend determining the proper developer time (for push or pull processing) by test developments using the same film exposed under the same lighting conditions, using the same exposure metering techniques. If it is not possible to test a specific film, lighting, and exposure combination, use the recommendations listed above. Generally, they will produce acceptable results.
Caution: There are many special purpose 'pushing' developers available from many manufacturers. These developers are specifically formulated for push processing. If you need to push process on a regular basis, or you want to do a substantial push process, use a developer specifically designed for push processing. These developers will almost always outperform a 'normal' developer when push processing. If the developer has specific instructions for processing that differ from what is presented here, use the manufacturer's recommendations as your starting point.
Optionally, you may 'tweak' the density of the processed film by making very small (fractional F-stop) adjustments to the developer time. Usually these minor adjustments will not adversely impact the quality of the processed image. This type of adjustment is usually done to fine tune all the small variances in a specific processing setup and procedure. Once this adjustment has been determined, the new developer time becomes your 'normal' time. All push and pull calculations are then derived from the new 'normal' time.
Approximate representation of increased grain with push processing, under a magnified view.
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This page last updated on 03/20/02