I need longer Dev. times

[Flotsam]

I've been using CPE to process my B&W film. The problem is that the continuous agitation seems to boost my contrast and cuts my times down to between 5 1/2 and 6 1/2 minutes. This is shorter than I would like and leaves no room for N minus development.

I am considering increasing the dilution of my developer in an attempt to lengthen my developing times. I am currently using FG7 at 1:15.
I know that I am going to have to retest my films but I am wondering if anyone has any thoughts on doing this or can suggest what I might expect.

Thanks

 

[Donald Miller]

Depends on the film and what process you are developing your negs for. Some films do not build contrast as rapidly or to as full an extent as others. I think that if I were faced with your situation then I would use a film and developer combination in which the testing has been done. I would look at the work that Sandy King has done on a variety of films as reported in the article on pyro developers on www.unblinkingeye.com

 

[gainer]

I don't know how much leeway you have for dilution before you run into starvation problems. If you think that might happen, a better way to get more development time is to reduce pH of the working solution. In the case of FG-7, I can't tell you much, but I think a small amount of boric acid might help. You could do a simple experiment with a scrap of film timed for two minutes or so. Add a measured amount of boric acid and see how long it takes to get the same density on another scrap. You could also use citric acid or perhaps even vinegar.

 

[Jorge Oliveira]

I think the easiest to start would be to dillute the dev 1+30 and retest.
If the results are not to your liking, then you may try the pH reduction test.

Jorge O

 

[Flotsam]

I just ran a test roll and thought that I'd share the results in case there is any interest here.

I cut the dilution from 1:15 with plain water to 1:24 (10ml to 240ml) and increased my time from 5 3/4 minutes to 9 minutes. The results are very good. The developer seemed to hold its activity and responded pretty much as expected. As with all slow films, The Pan F + doesn't tolerate over-development so I will probably back down to 8 minutes for my N development to hold my highlights down. This will still give me a long enough time for an N - 1 development. The experiment was a success that I will continue to use and expand to my other films.

I posted a scan of a print from that roll in the Critique Gallery. It doesn't do a damned thing to illustrate the process change but it was a nice day and I like the photo