PMK and HP5+ pushing development

Hi everybody.

I read last week in The Book of Pyro that you can use the dilution 2+4+100 to
<<develope more>>. I'm a bit confused because the author said that you don't
pushed the film in this way, if you have a 400 ISO film, expose the film to 400 ISO
again. So, I know that you don't push the film in this way. So, what's the point here? Don,t you just overdevelope the film?

What are your expérience about pushing HP5+ (800-1000 ISO) with PMK?
What are your dilution? Any tips.

Thank you

I've only used PMK at standard dilution. In my opinion it would be a poor choice for pushing. In fact, it needs generous exposure to produce good results. My guess is that the stronger mixture would not give much if any increase in shadow detail which is what you are trying to achieve with pushing. Maybe the author meant it as an N+ type of development, used when the subject contrast range is mild.

Pushing is underexposing and then overdeveloping to get a usable image. There is usually excessive contrast. The film is usually rated faster than it really is, and there is a corresponding loss of shadow detail

Developing longer than Normal to increase contrast for a low contrast scene falls under contrast control and is an integral part of the Zone System and other black-and-white contrast-control schemes. Here the film speed is not artificially increased

PMK is not the best developer for increasing contrast, and probably worse for pushing. Nevertheless, I get a good N+2 on Tri-X with a couple of trick. I use a 1:5:100 dilution, i.e., considerably more Solution B to increase developer dilution and extended development times. The film needs to be increased in speed about a stop, and the fogging is still considerable, needing to be printed through. The negs print alright, however.

Lately I've been experimenting with adding ascorbic acid (vitamin C) to PMK to help with expansions. I've had some interesting results with this. I mix a 0.5% ascorbic acid solution as stock solution C. So far, 2 parts A, 6 parts B and 1 part C to 100 parts water has yielded good results; I can get a pretty good N+2 at my N+1 time.

BTW, I don't push film very often, but I do use Zone System expansions quite a bit.

Best,

Doremus Scudder
www.DoremusScudder.com

My general impression is that pyro developers are not very good for push-processing. That's why I use Xtol for pushing, and Pyrocat for developing at box speed. I have tried several 1+2+100 dilutions, in an attempt to get bit more speed. No conclusive results there.