Standing development and Fomadon
One of my favourite developing techniques for B&W film is the so-called standing development method. There appears to be quite a bit of controversy connected to this way of producing negatives but I have found it to work very well, is reproducible and is not so stressful or need the same kind of accuracy as more traditional procedures. Specially, the development times are very laxed.
There seems to be as many versions of how to do it is as there are photographers. For me standing develoment is using Rodinal (or more exactly Fomadon R09 from FOMA in Bohemia) as the developer, diluted way beyond the normal recommendations (up to 1:100) and with development times of up to an hour. The purists do not agitate, but I normally do. Once.
I was curious to know how the developer acted. Was the full 60 minutes needed with any accuracy? In general accuracies are given as percentages. An accuracy of 15 seconds (Why 15? This is a likely timing-error due to the time it takes to fill and empty the tank.) in a 8-minute developing bath is about 3 %. Consequently 3 % percent of an hour is about two minutes. Do the last two minute’s action of the developer really matter that much? Sounds improbable.
A few test frames of 6×4.5 cm were shot with a Mamiya 645 on B&W-film Fomapan 400. I then developed the roll in steps, with no agitation. The procedure was as follow: with the film in the tank I added 2 dl of diluted developer, waited 15 minutes, added 1 dl, waited 20 minutes, added 1 dl, waited 10 minutes, added 1 dl and finally waited 5 minutes before fixing for about 10 minutes.
This way the larger part of the film would have been immersed in developer for 15+20+10+5=50 minutes, the next part for only 20+10+5=35 minutes, and so on. The same frame would then have been developed for 50, 35, 15 and 5 minutes. I purposely (quite cleverly if you ask me) used 2 dl for the first fill to get an assymmetric pattern on the film, only to know which part had been in there the longest.
According to my notes I used 5 ml of developer into 600 ml 20 degree Celsius water.
The picture below clearly shows the effect of different development times. This is straight from the scanner. No post-processing.
Fomapan 400 – a grainy film and perhaps not the best for R09, but it was what was there at the time. I prefer Fomapan 100 for my medium format cameras and R09.
Disregarding other photographical aspects of the picture, we can conclude that the wider and brighter band to the right corresponds to the first 2 dl of developer in the tank. This part of the film has been subjected to the developer for 50 minutes. The band to the far left is black for all practical purposes (actually one can see something in there, but nothing useful). That part has been developed for only 5 minutes which was clearly too short.
The middle band which is slightly darker than the rightmost one is developed for 35 minutes and the even darker to the left is developed for a mere 15 minutes.
To conclude: Some (less useful) developing action is noted at 5 and 15 minutes, but picture evolves after that and is useful after about half an hour. Left alone another half hour lightens the final image. The level of detail is not changed whether developed for 35 minutes or 50 minutes. What can be seen is that the lighter areas are almost entirely washed out in the 50 minute version and not quite so in the 35 minutes version.
Looking at the negative there are some structure in the leaves that is not visible in the picture above. Some pulling of sliders (notably exposure, recovery, shadows and highlights) in Aperture results in this:
Apparently post-processing can have a tremendous effect on the final result.
Post-processing can save development failures to some degree. In the above test even the 5 minute development would have given at least something to look at. These results prompted me to use 40 minute standing development for a while.
A general chemistry rule says that a reaction doubles its activity for every 10C temperature increase. A 1 degree Celsius change then corresponds to a change in activity of about 7.2 % (1.072^10=2). Assuming that the developer is linear in some respect, this translates to an equivalent change in time of some 4 minutes out of 60. We are clearly talking about a precision counted in minutes, and several of them, rather than seconds. Given the results of the test above we conclude that a precision of five minutes or thereabouts is entirely enough when dealing with standing development. In practice we of course use a timer with better precision to be able to repeat the process over and over, with exactly the expected result.
So why do I agitate once? It is because of the way the developer works. With no agitation, and no movement of the solution in the tank, the same developer will be over the same spot of film during the entire process. Now, dark and light parts of the image consume different amounts of developer, thus the local concentration of the developing agent will vary. In some rare occasions the more concentrated developer (that is to say, less exhausted) will cause local over-development giving strange halo-like brighter patches around darker objects. An agitation, or stir (or even swirl by some sources!), after some 20 minutes will even out the concentration and eliminate such halos.