Final Soak In PMK : LUSENET : B&W Photo - Film & Processing : One Thread

What is the purpose of the final, post-processing, bath in the original Pyro Developer?

-- Bill Mitchell (, March 12, 2001


To increase the stain. If I remember right, a soak in alkaline solution increases the stain. Since the used developer fills the pH requirements, and is readily available, it makes more sense than having a separate solution.

-- Charlie Strack (, March 12, 2001.

Does it stain the entire negative uniformly, or is there a differential stain in the areas of reduced silver?

-- Bill Mitchell (, March 12, 2001.

According to Hutchings, PMK does not stain during development, but only afterward, and the staining action is enhanced by an alkaline environment. I find that most of my staining takes place during the water bath I use for a stop, though I still put the film back in the developer for a couple of minutes after I fix it. When I used an acid stop, the staining took place during the final soak in the used developer. I definitely get better stain without the acid stop. Stain is directly proportional to silver in the developed negative.

-- Ed Buffaloe (, March 12, 2001.

Wonder if it could be used that way to stain negatives processed in other developers?

-- Bill Mitchell (, March 13, 2001.

My experience is that if you use a water stop and an alkaline fixer (like TF-4 from Photographers' Forumulary), you don't need the developer afterbath. PMK creates a "latent" image stain during the developing process that an alkaline solution makes visible afterward.

-- Brian Hinther (, March 13, 2001.

There is an article in Photo Techniques from a few months back on bleaching conventional negatives and redeveloping them in a pyro developer to get stain. It CAN be done.

-- Ed Buffaloe (, March 13, 2001.

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