Developing 120 black-and-white film

Revision history

2012/04/23: Initial release.
Notes from development: Increase duration of continuous wash. Consider switching to 1+3 developer dilution with 22 min. development time. Also consider reducing development time. Also, developer ended at 22°C.

2012/05/01: Increased continuous wash duration to 5 minutes. Added note to minimize handling of developer tank.
Notes from development: Started developer temp at 19.5° to allow for heating; ended at 21°C. Some artifacts along top edge of film ("top" relative to coiled cylinder inside the developing tank), see this example.

Equipment

1. Special equipment
1. Thermometer
2. Paterson "Universal" Development tank with 120 reel and force wash attachment
3. Drying clip set (one weighted)
2. Containers
1. Basin for water bath
2. 3 labeled beakers (500 mL)
3. 2 graduated cylinders (250 mL)
3. Chemicals
1. Kodak D-76 Developer stock solution (250 mL)
2. Kodak indicator stop bath (500 mL)
3. Clayton odorless rapid fixer (100 mL)
4. Used fixer
4. Other
1. Gloves
2. Paper towels

Setup

1. Create 20°C water bath. Ensure 20±5°C tap water is available for washing.
2. Mix 250 mL D-76 stock with 250 mL water in beaker. Before mixing, measure the stock temperature and adjust the water temperature to compensate. Place in water bath.
3. Pour 500 mL stop bath into a beaker in water bath. To make new stop bath, dilute 24 mL concentrate (caution: strong odor) to 1.5 L.
4. Pour 500 mL used fixer into a beaker in water bath. To make new fixer, mix 100 mL concentrate with 400 mL water.
5. Also prepare 500 mL of water.
6. Monitor developer temperature and adjust water bath to compensate.

Load film

1. Make a room as dark as possible.
2. With lights on, assemble film reel (ensure it is on the 120 setting) and center shaft. Remove paper band from film roll. Put film and reel in workspace, with development tank accessible. Turn off lights.
3. Start unrolling paper from spool. When you reach film, separate film from paper (it's not attached on this end) and let it coil up in your hand.
4. The other end of the film is taped to the paper. Un-tape the film and remove paper+spool from workspace. If tape is still attached to film, fold it over so no sticky parts are exposed.
5. Insert this end into Paterson reel. Once it clears the bearings, smoothly walk film onto the roll. Try to keep film roll parallel with reel. If film gets stuck, try smaller motions.
6. Install reel into tank and close lid.

Process

1. Check developer temperature and adjust if necessary.
2. Pour in developer. Perform 10 cycles of inversions at 1 Hz. After agitation, allow water to flow to bottom, then tap bottom edge of jar on work surface to dislodge air bubbles. 
3. Agitate (10 cycles at 1 Hz, then dislodge air bubbles) every minute.  Minimize handling to reduce body heat transfer. Total development time should be 12 minutes.
4. Pour developer back into beaker and pour in stop bath. Agitate continuously for 30 seconds. 
5. Pour stop bath back into beaker and pour in water. Agitate continuously for 10 seconds. Pour water down drain.
6. Pour in fixer. Agitate every minute for 5 minutes. Pour fixer back into beaker.
7. Run water through force washer for 5 minutes.
8. Open tank and check that film has cleared. Close tank.
9. Wash in batches with continuous agitation for 5 minutes, refreshing water every minute. Use distilled water for last batch.

Cleanup

1. Hang up film with weighted clips to dry.
2. Discard developer.
3. Pour stop bath back into storage container.
4. Pour fixer into used fixer container.

References

YouTube instructional videos:
How to Develop Film
Loading 120 film into a Paterson plastic reel

Kodak D-76 Developer datasheet
Ilford Delta 100 film datasheet