B&W Negative Tray Developing: Uneven Development

Question

Shooting on an old Graphlex Speed Graphic 4x5 using tray development I am having consistent problems with uneven development, noticeable especially in the skies.

Update: I get perfectly even development with either developer/time combo listed below when I use a tank.

I am developing in trays. My trays are 5x7, plastic and have channels, not ridges. I ensure my chemicals are always exactly 20 degrees celsius.

My normal technique (though I have varied this: see notes below)

1. submerge the negative emulsion side up, and rock the tray 10 times each minute of development

2. move it to a stop bath for about 1 minute with constant agitation,

3. move it to a fixing bath for 4 minutes, rocking the tray 10 times each minute

4. wash it for about 5 minutes

5. submerge it in a quick wetting agent bath before hang drying it.

Variations I've tried that have resulted in uneven development:

• Films: Arista EDU 100 and Ilford Delta 100.
• Lenses: Ektar 127mm and Schneider Super Angulon 90mm.
• Developers:
  • Ilfosol 3 (1:9) at 5 minutes and 7.4 minutes
  • Kodak D-76 developer (1:1) at 10 minutes
• Fixer:
  • 4 minutes with fresh fixer.
  • Extended "re-fixing" for 10+ minutes with fresh fixer.
• Agitation: Periodic and regular agitation.

What could be causing this uneven development?

Scanned Examples

These are from a cloudless day. I've darkened them to emphasize the uneven sky.

1. Arista EDU 100, Ilfosol 3 for 5 minutes with periodic agitation.

2. Arista EDU 100, D-76 for 10 minutes with periodic agitation.

Answer 1

A lack of uniformity in a mundane expanse such as the sky likely traces back to the developing technique. The first thing I would do is re-fix these negatives in the hope that they were under-fixed. The rule of thumb is to immerse a small piece of undeveloped film in the fixer. This is performed in a lighted room. Time how long it takes for the fixer to clear the film, then double this for the appropriate fix time. Better too long than to short.

That being said, development is dependent on the developer, which is mainly water, infusing into the emulsion, so it can go to work. The emulsion binder is gelatin, a long chain polymer. It is chosen because it is transparent, flexible, and has low solubility. When first wet by the waters of the developer, it swells. This action opens up the structure allowing the developer goodies to enter and do their work.

If uniformity is the problem, likely the developing time is too short. My first advice is to select a developer formula that takes more time to work. How about ten minutes obtained by formula, dilution or temperature?

Next let’s talk about “bromine drag”. As the developer works, it reduces the silver salt crystal to its two component parts. The silver portion, now metallic silver, remains embedded in the gelatin; the halogen portion is dissolved and is flushed out by agitation. As the halogen exits, its presence retards development until completely flushed out because fresh developer can’t get in. If the film is in a stagnant fluid, halogens, heavier than the surrounds, flow downward by gravity. The dots on the edge printing will divulge this by showing a faint comma-like tail. Look for this as a sign of insufficient agitation.

Again, my advice is a longer developing time.

Answer 2

I feel your processing times are off.

I agree with Marcus that the development time for your sheet film is too short. It also looks as though you may not have covered the sheet of film completely at once with developer.
Either way, ensure that you have sufficient solution to fully immerse each sheet of film.

Change your dilution to allow longer development times. Start with 10 minutes as a minimum. Don't be in a hurry. This step determines your success. Longer processing times minimize timing variation errors due to immersion, draining, and transfer times.

There are a few different techniques to tray develop sheet film. Some use special soft brushes soaked in developer to "paint" the developer onto the emulsion. Some tape the film to the centre of the bottom of a dry tray and pour the developer onto it. More often, the sheet of film is held by the notched corner in the right hand (so the emulsion faces up) and slid into the tray of developer in one smooth motion.

For accurate repeatable results, sensitometric processing requires fastening the film with tape and rocking the tray determines the agitation. Whether you fasten the film or not, the agitation technique is the same, more or less.

Sensitometric Agitation Technique for Tray Processing Sheet Film
(Practice this technique first with water in a normally lit room until you can do it neatly.)

The sequence: - Pour the developer into the tray. - Start the timer. - Lift the closest edge of the tray about a quarter of an inch and lower it to the counter. - Lift the right-hand edge about a quarter of an inch and then lower it to the counter. - Lift the closest edge again and lower it to the counter. - Lift the left-hand edge and lower it to the counter. - Repeat this rhythmic cycle until the end of the development time.

The timing: For the timing, take one second to lift each edge and another second to lower it. Two seconds per side; front, right, front, left, front, right, front, … etc.

At the end of development, replace the developer with an acid stop bath to change the pH of the alkaline developer to stop the development of the latent image. The surface of the emulsion is fully swollen with developer and is easily scratched. Handle it with great care.

Allow 30 seconds to a minute for the stop bath.

Fix the film for twice the time required to clear the film.
NOTE: To establish this time precisely, immerse a piece of unprocessed film in fixer and record how long it takes to completely clear. Double the time it takes to turn clear to get the required fixing time for processing your sheet of film.

Now, you can turn the lights on.

At this point in the process, the emulsion is laden with fixer and silver salts which can destroy your image in time if not removed. The residual chemicals must be washed free of the emulsion which takes time. Wash your film for a minimum of 30 minutes in running water. It doesn't need to be a torrent. It just has to be sufficient to change the water in the tray a couple of times a minute. Take care to keep wash water temperatures as constant and consistent as you did for the rest of the process. Film emulsion is susceptible to thermal shock when wet and can reticulate easily which will ruin the image.

You may or may not need to use a wetting solution after a thorough washing.

Hang up to drip-dry in a dust-free place.

Admire your excellent results

If you want to check the regularity and homogeneity of your processing, fog a sheet of film evenly and carefully process it as described above. Any processing irregularities will be exposed :) as there will be no image to distract you. Film can be fogged by putting a sheet of film face-up on the darkroom counter top and turning on a small indirect light very briefly.

Answer 3

I don't think your uneveness is limited to the sky, but your entire image is uneven. You just happen to notice it in the sky where processing imperfections would show up best. However, are you certain that these imperfections are created during the processing of the negative? Do you get the same imperfections in the same locations regardless of how you print your image? Incidentally, are those images above scans or prints?

Your cheapest fix would be to mix your processing solutions in purified water. You can buy it by the gallon for next-to-nothing at your local grocer. I'm certain that your developing solution has been compromised by your particular water chemistry.