Tuesday, 26 August 2014

Diafine for Medium Format Monochrome

I have recently returned to using my 6x6 cameras and am taking some time out to investigate how the move back to film may change some of my monochrome work. On the face of it there is nothing I cannot shoot digitally. If fact I have more choice of lenses and cameras in that genre but having spent many years in the past shooting 120 film and making silver prints I know that there is an aesthetic difference in the final output, especially when making large prints and I need to see If I can achieve that with a hybrid film and digital workflow. This is not to be regarded as a quality issue, as both film ( I am only considering 120/220) and digital produce outstanding results when a regulated professional workflow is used. Also this is not a technical investigation with detailed references to spectrometry, chemistry etc, but a simple see what works and use it approach.

The whole subject of what film to use, processing, scanning and final print output is possibly the subject of a much wider examination so based upon some previous experience and some online research I have started my own mini project to determine a good best practice fit to two picture making scenarios, still and moving.

Film Stock

Studio / Outdoor Still LIfe (Camera on a Tripod)

A slow film can be used as the slow shutter speeds do not become a problem. Online research shows that for my taste (its all about aesthetics) Fuji Across 100 ISO is suitable, obtainable and reasonably priced.

Street Photography (Camera Hand Held)

A faster film is needed to allow shutter speeds of 1/125 or faster with f8 to f16 aperture.
From previous experience Kodak Tri X ISO 400 and Kodak TMax 400 ISO 400 produce suitable results and can be pushed to higher ISO ratings with suitable developer.

Developing Methodology

The two options available here are to either send it to a good quality processing company or do it myself. My preferred processing house is Peak Imaging. They have a good track record with quality and offer OCA students a discount. They process all their B&W film in Kodak XTol at full strength and can push process if requested. As a reference their output is good and I will use this as a datum.

The second option is process the film myself. Having spent over 20 years (70s and 80s) doing it in the past there is no learning curve for film loading etc although I have to purchase a tank, chemicals and bottles. There is however a wide choice of developing chemicals and formulae which can be used, together with various dilutions, timings and agitation routines, all of which will effect the outcome of the process.

Developer Choice

From previous experiences I had had good results using a wide range of Ilford and Kodak products. ID11, HC110, Perceptol etc etc at their recommended box temperatures and durations. Those negatives were then enlarged and prints made in either a condenser or diffuser type enlarger. The negative contrast needed to be different depending on the type of enlarger being used. Typically the condenser enlarger produced contrasty prints and therefore did not require contrasty negatives.  
The negatives I will produce are to be scanned and this produces a different criteria for the film processing. I am looking for a negative that has a full range of tones and requires a minimal amount of post processing in CS5. From research and anecdotal evidence a 2 bath developer is the way forward and it is from the work of the late Barry Thornton that I have taken advice. The ultimate for B&W film success is to expose to give the maximum detail in the shadows and as little development to the highlights so as to retain detail.   Heinrich Sto√ęckler had invented a 2 bath developer before 1939 and this was popular with Leica users and Ansel Adams used a version of Kodak D23. The formula for all of these and Barry's own version are available to mix from base chemicals. Diafine is an American 2 bath developer that has a proven track record with research carried out by Stephen Schaub at www.figitalrevolution.com  
Diafine is not readily available in the UK but I have sourced a 1 gallon (US) kit from Germany and made up the solutions A and B. Two bath developers works as follows.
The film is ’developed’ in Bath A with agitation every half or full minute. Actually little development takes place. Mostly the film is becoming saturated with the developing solution. However, some development does take place and agitation is important to prevent streaking. The solution is then poured off and saved. Drain the tank well but don’t rinse or use a stop bath. Then pour in Bath B, and after a quick rap of the tank on a hard surface to dislodge any airbells, let the tank stand still with no agitation for three minutes or so when all development has ceased. In the highlight regions where the developed silver will be densest, the developer available in the emulsion is soon exhausted and development halts, thus automatically limiting the density of the negative at that point. The more the exposure, and the denser the highlight, the faster development ceases. In the shadows, though, there is little silver to reduce and there is enough developer to keep working there to push up the shadow detail density. The less light the negative received at this point the longer the development proceeds.  Unlike conventional developers there is nothing to be gained by changing temperature or times. All films, whether exposed at ISO 100 or ISO 1000 can be processed at around 20c and in each bath for at least 3 minutes minimum. The solutions are used many times and although they become discoloured there is no loss of performance for many months. There is no stop bath required other than a rinse in water and then use a rapid film fixer for 10 mins and wash as normal, using a wetting agent and distilled water for the final rinse to eliminate drying marks. The advantages of this developer are numerous. It is easy to use, requires no special darkroom techniques, accommodates various film types and ratings in the same tank and produces negatives of extremely fine grain and a tonal range that allows the scanner to pick up all the shadow detail with no blown highlights.

Results

Film used so far is Across rated at 160, TMax 400 rated at 560 and Tri X rated at 400 and 1000. 
As one would expect the Acros has almost no grain, extremely full range of tones and a creamy feel that for fine art photography would make it sublime. The TMax 400 is extremely good for general photography with a grain structure that is pleasant. Tmax 400 has a tabular grain emulsion and is perhaps not best suited to the 2 bath process.  The Tri X is gorgeous to look at through a loupe and scans extremely well. It has a reputation for handling contrast very well and with the 2 bath this is extended to give an amazing range of tonality. Diafine recommend rating it at ISO 1000 and that makes it extremely usable in low light although a roll at box speed look perfect.

It is difficult to show the results on the web. The tonality, the minute shadow detail and the creamy nature of the output is marginally different to digital images and only manifests itself in a print that can be inspected under good light.

I have also found that I am getting different results from my scanner (Epson V750 wet mounted) with different software. For colour negatives I use Silverfast 8 and find the control to be fine but for monochrome at 16 bit the Epson software is giving me a richer range of tones. To enhance the film "look" I also want to make as many tonal adjustments at the scanning stage rather than in Post Processing. The less digital manipulation the better the result will be.

Conclusions

Initially I am pleased to have gone down the 2 bath developer route. It offers benefits over developers that worked well for enlarger use as it provides a full tone negative that is maybe a bit flat (linear) and gives the scanner a better opportunity to capture shadow and highlight detail. I will limit my film stock to Acros, and Tri X once the T Max has been used. With 2 films I can cover most situations of lighting and technique in a range from 160 to 1000 ISO. Further test rolls of Across to be shot at box speed of 100 ISO.

None of this work with film (I personally reject the word analogue to describe this) is going to show huge improvements over my digital output. The differences are esoteric and marginal. I enjoy using the MF cameras (Mamiya 6 and Hasselblad 500 CM) because they require an engagement at another level. The frames are restricted, there is a tenderness about using classic cameras and there is an appreciation about light falling onto silver with its endless range of tone and contrast. The classic lenses produce sharp yet rounded images with bokeh that is not seen in modern equipment. When it all comes together the images have an engaging aesthetic that sets them apart from my other work. Some will say that this is wasting time and it would be better to move forward with technology and look at more contemporary techniques. That may be true but I am convinced that the time spent trying is worthwhile,

Below are two images from T Max 400 rated at 560 Part A 4.5m + Part B 4.5m







2 comments:

  1. I knew Barry Thornton quite well - he passed too early - did you consider any of his developers, or Peter Hogan's?

    ReplyDelete
  2. I have the chemicals to make Barry's and D23 but for now I will stick with Diafine. I think the difference amongst all those with similar formula may be too difficult for me to see anyway. I know its a pain compared to digital but the method and the final print quality is worth it. It makes me think more about what I am doing throughout the entire process.
    I enjoy reading Barry's words, RIP a genius.

    ReplyDelete