Uneven Film Processing Development

She-oaks, Canning River, Perth, with Ilford FP4 stand developed in LC29

5 tips on how to avoid uneven film development

Uneven film development can occur during any film processing. Insufficient agitation is a major contributing factor to uneven development.

Uneven film development can occur with Stand development, a minimal agitation development technique. It offers uniques benefits of increased film speed and several f-stops increase in dynamic range. Unlike regular developing processes, stand development can suffer from the potential problems of uneven film processing. These problems can include froth and bubble developing patterns, bromide drag, air bells, reel spots, uneven negative density, and spots. I have suggested some possible solutions below.

6 Suggestions on how to avoid uneven film development with stand development film processing

  1. Pre-soak your film

    Use plain water at developing temperature to pre-soak your film.pre-soaking films

  2. Use sufficient developer volume

    Unlike other developing methods, processing solutions must cover the film entirely when the tank is left in vertical position for stand development.

  3. Use correct film developer dilution

    Developer activity is dependent on developer’s film capacity

  4. Give sufficient film agitation

    Avoid uneven film edge development, bromide drag and air bells.

  5. Control your developing temperature

    Use a water-bath for consistent processing temperature.

  6. Avoid short development times

    Developing times of less than 5 minutes is too short to ensure even development.

Use sufficient developer volume.

stand development error
Insufficient solution causing uneven development

Stand development uses larger fluid volumes in tanks than used on roller bases. The above image shows the result of a partially filled tank on film development. The lower half the film was immersed continuously while the upper half received less development. It leaves a distinct line across the film showing two sides with very different film densities.

stand development problems
Froth and bubbles leave developed froth and bubble patterns.

Always ensure that your solutions are at least one centimeter above the film reel, avoiding any film from protruding into the air. The fluid – air interface is the perfect position for froth and bubbles to accumulate on the film surface. Consequently, they create different rates of development, leaving a permanent density change on your negative. Even with minimal agitation in stand development bubbles and froth can still be formed. Then it sits on the emulsion for minutes between agitation. Avoid using water from aerating faucets when making your solutions up.

Calculating film developer capacity

film capacity stand development
Know your the film capacity of your developer

For effective stand development use a minimum amount of developer in a highly diluted form. However, you will need sufficient developer activity to potentially develop all of the exposed film properly. Using less developer than recommended by the manufacturer means you risk under-developing your film in the shadows and mid-tones. Under-developing film does not yeild the same result as stand developing.

What is the minimum developer I require?

You need two numbers to calculate your developer’s film capacity. Firstly, is the concentrate volume of the developer. Secondly, is the total number of films that concentrate can develop.

Let’s, for example, take a 250ml bottle of concentrated developer. On its information sheet (printed on the side of the bottle or manufacturer’s web site) it states one full bottle can develop a total of 12, 35mm films. In other words, the 250mls of concentrate has the capacity to fully develop 12 films. Dividing 250ml by 12 films (250/12) and you get 20.83mls per film. It is more practical to round this up to 21mls. So, you need 21mls of developer concentrate (stock solution) in your tank per film.

The final volume of water you use to dilute the developer concentrate is the working solution. For example, if you require 800mls of developer solution to cover your film, then your final dilution would be 800mls working solution minus 21mls concentrated developer = 779mls water. In other words, to make your working solution you would take 21mls of developer concentrate and add 779mls of water giving a total of 800mls.

Film Area Equivalents

Use the table below to help you calculate your developer’s film capacity. For example, if the total concentrate has a capacity of 12 x 35mm films, then equals 12 film equivalents. This is the same as 12 x 4 sheets = 48 sheets of 4×5 film. Likewise, the same bottle has the capacity of 12 x 1 roll film = 12 rolls of 120 film or 12 x 1 sheet of 8×10 film = 12 sheets of 8×10 film.

1 Film Area Equivalent=1 x 35mm film of 36 exposure
•based on 8×10 inch surface area=1 x 120 format roll film
=4 sheets x 4×5 inch film
=1 sheet x 8×10 inch film

Give sufficient agitation

uneven edge development
Slight drop in density of the right hand edge shows uneven development from film reel

Uneven Edge Development

Certainly, uneven edge development can be a frustrating problem with film developed in reels. To offset this problem you can try increasing the frequency of agitation without increasing the overall amount of agitation (film tank inversions) received.

For example, in the two tables below I have illustrated how to do this. Table 1 shows my stand developing times of 30 minutes total time, with a total of 55 tank inversions in 55 seconds. However, I have experienced some uneven edge development. So, I have increased the frequency of agitation as shown in Table 2.

Now instead of 4 main agitation periods in Table 1, I have 6 agitation periods in Table 2. In Table 1 I use 5 inversions in 5 seconds. Consequently, I have had to adjust for the additional agitation frequency and have reduced agitation to 3 inversions in 3 seconds. Both Table 1 and 2 have the same total number of 55 inversions in 55 seconds.

Adjusting Agitation Frequency

Table 1Original Processing Procedure
Developing TimesUse a water bath for temperature control
T 33 min – 30 minPre-soak film in water at 20ºC
T 30 min – 29minpour in 1400mls working solution developer,
(15ml of LC29 plus 1385mls water)
invert tank 40 times in 40 seconds
T 28 mininvert tank 5 times in 5 seconds
T 20 mininvert tank 5 times in 5 seconds
T 10 mininvert tank 5 times in 5 seconds
final 20 secondsremaining 20 seconds pour out developer
Total 55 inversions in 55 seconds

Increase Frequency without Increasing Total Agitation

Table 2New Processing Procedure
Developing TimesUse a water bath for temperature control
T 33 min – 30 minPre-soak film in water at 20ºC
T 30 min – 29 minpour in 1400mls working solution developer,
(15ml of LC29 plus 1385mls water)
invert tank 40 times in 40 seconds
T 28 mininvert tank 3 times in 3 seconds
T 23 mininvert tank 3 times in 3 seconds
T 18 mininvert tank 3 times in 3 seconds
T 13 mininvert tank 3 times in 3 seconds
T 8 mininvert tank 3 times in 3 seconds
final 20 secondspour out developer
Total 55 inversions in 55 seconds

Avoiding bromide drag and air bells

Low agitation techniques such as stand development are more likely to suffer bromide drag than normal film processing. You will notice bromide drag more so in the heavily exposed area of negatives, rather than the thin underexposed portion of negative. Even though the negative below was developed using a temperature-controlled water-bath, it did not prevent bromide drag.

stand development bromide drag
Film negative showing bromide drag

Bromide drag

For example, look carefully at the section of negative pointed to by the red arrow. Dots 1 through to 10 have heavily exposed circles which have developed black. Developer activity in the dense areas of the negative means the developer has been much more active here than in the thin shadow areas. In contrast, the immediate dot surroundings have received very little exposure and range from clear film base to light grey.

Bromide, a by-product of developing activity, has drifted slowly downward while the film has stood unagitated. Bromide inhibits development, so a lighter density streak has occurred under each dot, just visible in the very light grey areas. It is as if the white around the dot circles has been dragged or leaked out into grey parts of the negative. Bromide drag is not so obvious in the bottom circles as it is in the top circles. Bromide drag does not occur equally across a negative.

My personal tests, in contrast to website sources, indicate that temperature control alone does not reduce or eliminate bromide drag. This film was processed at 20ºC using a water-bath. My advice is that increasing agitation frequency reduces the presence of bromide drag.

Air Bells and Film Reel Contact

Air bells are formed by trapped air bubbles on the film’s emulsion. Consequently, they disrupt even development. Air bells form as underdeveloped, almost film base clear, circular shapes. They print as dark black circles.

In the image above, dots 6,8 and 9 have dark round areas, most likely formed by film reel contact. As before, physical contact with the emulsion creates conditions for uneven film development. Therefore, to avoid air bubbles you can rap the base of the tank gently on the table to dislodge bubbles.

Pre-soaking

You can also try pre-soaking your film. Pre-soaking may prevent air bubbles from becoming trapped by fully wetting the emulsion prior to developing. Another option is to avoid mixing your working solutions from aerated faucets which introduce disolved gas into the water.

Controlling your developing temperature.

Stand development
Use an esky for temperature control to avoid uneven film development

Unlike regular development, stand development uses long developing times with minimal agitation. Use an insulated food or drinks container with a fitting lid to maintain a constant developing temperature. Even temperature control is essential to give you consistency when processing several films from one project. Good temperature control will also give you repeatable results into the future.

Chamonix camera set up location for main photo top of page

Main black and white image top: Sheoaks, Canning River, Perth. Chamonix 45F-2, 300mm Nikkor lens, Stand Developed Ilford FP4 30seconds @f9

A useful reference is The Art of Photography 2nd edition, Bruce Barnbaum, 2017  Rockynook , also take a look at my earlier article on Stand Development

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