Film Processing Procedures that Ensure High-Quality Results
Certain general working procedures can be followed in film processing to ensure consistent high-quality results.
These include the following:
■ Read, follow, and understand all technical and safety data before processing the film.
■ Ascertain your equipment and working area are clean, dry, and properly functioning.
■ Seal any light leaks in film-loading and film processing areas.
■ Lay out your equipment in a manner so you can find it in the dark.
■ Utilize durable, plastic funnels, graduates, mixing pails, stirring rods, and bottles, which are easy to clean, inexpensive, and applicable to most processes. Avoid possible contamination by using separate graduates and containers for developer and fixer. Rinse all mixing equipment before and after each use.
■ Once a developer is mixed into a working solution, store it in a clean brown plastic container, removing as much air as possible from the container, to ensure maximum life.
■ Do not exceed the working capacities (the amount of film that may be processed) of the solutions.
■ Mix the developer with distilled water to ensure consistency, especially in areas with problematic water.
■ Employ the same, accurate thermometer to ensure solutions are at their proper operating temperatures and for processing consistency.
■ Presoaking film removes the antihalation backing incorporated into the emulsion, increasing the potential for streaking. As the developer has to displace the water absorbed by the emulsion during the presoak, you may have to extend the developing time. Some people think that presoaking the film for 1–2 minutes before beginning to process prepares the film for developer and eliminates air bubbles, thus helping deliver superior quality. Try it and decide for yourself.
■ Follow recommended agitation patterns for each step of processing. With small single- or double-reel tanks, drop the loaded film reel into the developer and attach the top to the tank. Firmly tap the tank on a flat surface at 30 degrees to dislodge any air bubbles. Provide initial agitation of five to seven inversion cycles in 5 seconds, i.e. extend your arm and vigorously twist your wrist 180 degrees. Then repeat this agitation procedure at 30 second intervals for the rest of the development time.
■ Include drain time in each processing step.
■ Stop bath rapidly changes the pH of film, causing the action of the developer to cease and also extending the life of the fixer. Prepare an acid stop bath by mixing it from a 28 per cent stock solution of acetic acid to avoid the problems that can occur when working with the highly concentrated 99 per cent glacial acetic acid. Dilute the 28 per cent stock solution to its recommended working strength. Use it one time (one shot) and dispose of it. If you want to reuse the stop bath, get one that contains an indicator dye that changes color to inform you when the solution is becoming exhausted. Discard the indicator stop after its orange color disappears. If you wait for it to turn purple, it may already be exhausted. Indicator stop bath may be used to make all film and paper stop baths. If you choose not to use a stop bath, rinse the film twice in the processing tank, with water.
■ Fixer or hypo comes in two forms: regular, which consists mainly of sodium thiosulfate powder, and rapid, which is usually ammonium thiosulfate in a liquid form. Either may be used for most processes. Check to make sure the dilution is correct for the process being carried out. Both types may be reused. Keep a record of the number of rolls processed or perform a hypo test to see when the fixer has become exhausted due to silver saturation. The general rule of thumb is to fix for twice as long as it takes the film to clear.
■ Hypo check is necessary to ensure the fixer is not exhausted due to use, age (oxidation) or other contamination. The most accurate method to determine the fixer’s efficiency is to take a small piece of exposed film and fix it. The film should clear in about 30 seconds. If it takes more than a minute to clear dump the fixer. Some films, such as T-MAX, will have a pinkish cast after being properly fixed and will not completely clear until they have been treated in a hypo clearing agent. Although not as accurate, a hypo test solution can provide a visual guide to check the fixer for exhaustion. This test solution can be purchased commercially or made by following the formula at the end of this chart.
■ Using a film washer will facilitate the washing process. The constant turbulence created by introducing water and air into the bottom of the washing chamber helps remove hypo and debris. However, film may be washed in the processing tank. Make certain that the water is changed often, at least 12 complete changes of water, or get a film washer that does this automatically.
■ Use a hypo clearing agent to help remove fixer residue and reduce washing time.
■ Place the film in a wetting agent for about 2 minutes with light agitation before hanging it to dry in a dust-free area. Always mix the wetting agent with distilled water. Dispose of the used solution after each use. Do not use heat or forced air to speed film drying.
■ If the water you are using is extremely hard or if you are experiencing problems with particles drying on the film, try this procedure even though it violates the general rule not to touch film. On removing the film from the wetting agent, shake off excess solution in the sink. Hang film up and clip it on the bottom. Make sure your fingers are clean and smooth, put your index and middle fingers in the wetting solution and shake them off. Now use these two fingers to gently squeegee both sides of the film. With a lint-free disposable towel, such as a Photo-Wipe, carefully wipe the nonemulsion (shiny) side of the film from top to bottom. Do not wipe the emulsion side, as it is still soft and can be damaged easily. Hold the film at a slight angle with one hand. Using the other hand, slowly bring the disposable towel down the full length of the film. Keep your eye on the film just behind where the towel has passed to check for any spots, streaks, or particles. If any are visible, go back and remove them. A rainbow effect on the film surface indicates that you are carrying out the procedure correctly. Allow to air dry.
■ After the film is dry, place it in archival plastic sleeves or acid-free paper envelopes. Store it in a cool, dry place. Do not use glassine, kraft paper, or polyvinyl chloride (PVC) materials for storage, as they contain substances that can damage film over time.
■ Record all yours procedures in your Resource Guide. List the date, type of film, developer, time, and temperature; any procedures that are different from normal; the outcome; and the changes to be made in working methods if a similar situation is encountered in the future.
■ Refrigerate or freeze the film in a zip-lock plastic bag before and after exposure for maximum quality. Let the film reach its operating temperature before loading, exposing, or processing it.
■ Problems may be remedied by scanning the film and then using imaging software to make adjustments or corrections.
Excerpted from Photographic Possibilities: The Expressive Use of Equipment, Ideas, Materials, and Processes, 3rd Edition by Robert Hirsch ©2011 Elsevier Inc. All Rights Reserved.
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