Reversal processing for black and white films

by George Huczek

Step Preparation Notes
1. First Ilford Bromophen 1:1 Develop for 12 minutes at 68° F
Development or Ilford universal paper developer 1:15 5 second inversion every 15 seconds.
Add 12 g of sodium thiosulfate (hypo) per litre Tap tank gently to dislodge air bells.
of working strength developer for 100 ISO films
or 8 g per litre for 50 ISO films Save used developer for step 8.
2. First Wash Fresh water at 68° F. Fill and invert 5 times
using the standard rinse procedure.
3. Bleaching Solution A: potassium permanganate 2g/500mL 5 minutes of bleaching with continuous agitation
Solution B: sulfuric acid 10 mL conc + 490 mL Vigorous agitation is desirable.
water (10g potassium dichromate in 1L water plus
Mix equal parts of A and B prior to bleaching. 10 mL sulfuric acid is an alternative bleach)
4. Second Fresh water at 68° F. Fill and invert 5 times
Wash using the standard rinse procedure.
5. Clearing Add 25g sodium (or potassium) metabisulfite to 2 minutes
enough water to make a 1 litre solution (4 inversions per 5 seconds)
(for dichromate bleach use 50g of anhydrous
sodium sulfite in 1L of water)
6. Third Fresh water at 68° F. Fill and invert 5 times
Wash using the standard rinse procedure.
7. Film Open developing tank Expose to light for about 30 seconds
Exposure Carefully unwind film from reel. away from 100W bulb. Time not critical
After exposure wind film back on reel and place
in developing tank.
8. Second Use same developer as in step 1. Time is not critical.
Development or use fresh developer with no hypo added to
improve shadow regions
9. Fourth Fresh water at 68° F. Fill and invert 5 times
Wash using the standard rinse procedure.
10. Fixing Optional step. Use any available fixer. Use a standard fixing technique and time for the
available fixer being used.
11. Fifth Wash thoroughly
Wash discarding water periodically.
12. Wetting 1 or 2 drops Photoflo per 500 mL distilled water 30 second immersion. Tap tank to remove air bells.
13. Drying Air dry overnight. Do not squeegee film.
Emulsion is very soft when wet.
Cut and mount dried slides.

Step 1: First Development
The latent image is developed on film, like in regular black and white processing to produce a negative. Note the presence of a small amount of sodium thiosulfate (fixer) included with the developer. As development is taking place, the fixer will act on both the exposed and unexposed regions of the film. Those regions heavily exposed will develop before the fixer has a chance to act. Areas slightly exposed or unexposed on the film will be affected by the fixer. Unexposed areas (which will eventually turn out dark on the positive image of the slide) will have a slight amount of silver halides removed, so that even in the dark regions a small amount of transparency will exist in the finished slide. This will provide the proper contrast. Do not discard the developer. It can be used again in step 8, but fresh develop without added fixer will give slightly different results, with improved shadow regions. Tests will have to be done to use this process on other films, or with other developers.

Step 2: First Wash
An acid stop bath is not used in this step. Use a plain water rinse. The first rinse will decrease the alkalinity of the developer quickly. Invert the tank a few times, discard the water and refill at least 5 times. Water temperature should be kept close to 68F. Improper water temperature can cause reticulation.

Step 3: Bleaching
Two different bleaches are indicated in the table. Either one will work. Potassium permanganate is less hazardous to use than potassium dichromate. The purpose of the bleach is to remove the silver formed on the film by the developer. In a black and white negative, areas on the film receiving the most exposure turn out darkest. These areas print lightest. On a slide, the lightest areas need to appear light. The bleaches are strong oxidizing agents. They will act on the silver on the film surface, but leave the unexposed silver halides intact.

Step 4: Second Wash
Follow a similar procedure as in step 2.

Step 5: Clearing
This will remove any stain remaining on the film by the bleach.

Step 6: Third Wash
As in step 2.

Step 7: Film Exposure
At this point what remains on the film is the unexposed silver halide. Any exposed regions, acted on by the developer, were removed by the bleach. The film now has to be exposed to light. Remove the film from the developing tank. Carefully unwind it from the developing reel. Exposure can be to any type of light source.

Step 8: Second Development
Carefully wind the film back on the reel and place it back in the developing tank. Redevelop the film for about 6 minutes, using either the discarded developer from Step 1, or fresh developer without the added fixer. Discard the developer after this step. This is a one-shot process. Replenishing the developer and reusing it will give unpredictable results.

Step 9: Fourth Wash
As in step 2.

Step 10. Fixing
There should not be very much material remaining on the film to fix. This step is optional. It will only take a few minutes, and is worthwhile. A hardener may be used in the fixer.

Step 11: Fifth Wash
As in step 2

Step 12: Wetting agent
Make sure that distilled water is used. Use very little wetting agent. This step will help to prevent drying marks on the film.

Step 13: Drying
The emulsion is very soft. Do not squeegee the film. Hang it up to dry overnight. Step 12 will prevent drying marks. Mount as with any other transparencies, in slide mounts.