Pyro and Photo Flo

[LuisR]

I am going to experiment with using the Photographer's Formulary 2 part liquid Pyro chemistry for the first time. I ran across information that states not to use Photo-Flo or similar chemicals on Pyro processed films as it will remove the stain. Where I live we have hard well water so not using Photo-Flo will result in water spotting on film. Can experienced users of Pyro shed some light on this? In addition, the PF instructions talk about using a Pyro after bath (meaning after fixing). My understanding was that after developing in Pyro and fixing in PF's TF-4 alkali fixer the film is just washed in water for about 45min. It is also stated that using TF-4 does not require a hypo clearing agent. Can the use of a hypo clearing agent speed up the wash process, and will using this chemical also wash away the Pyro stain? Thanks for your informed comments.

[IanG]

Luis, there's a lot of rubbish written about these issues and saying don't use Photoflow and re-using the developer as an after bath after fixing are some of them. Others are saying don't use a stop bath and only using an alkaline fixer.

I recommend you read Sandy King's article on using Pyro developers.

Ian

[Peter Lewin]

Luis, I can only tell you about my own processing; I have been using PMK for a long time, and as far as I can tell, nothing I'm doing has had a damaging effect on the stain. First, Gordon Hutchings no longer recommends the after bath in used developer; it turns out that the after-bath simply increased overall stain, not the image-specific stain that you want. So my sequence is pre-soak - PMK - water stop bath - TF-4 - wash. After washing for 25-30 minutes, I do use a little Photo-Flo in distilled water before hanging up the negs to dry. I had never heard any suggestions to avoid the Photo-Flo. I have never used hypo clear on negatives. The wash time is that recommended by both PF for TF-4 and by Hutchings, who says that 25-30 minutes of washing maximizes stain.

[LuisR]

Ian and Peter, thank you very much for your info. I am leaning towards Pyrocat-HD from Bostick-Sullivan liquid concentrates based of Sandy's article and other forum posts. I do have another question, can it be mixed just prior to using for just the amount needed or does it have to be mixed into a stock solution? I have mixed Rodinal for just the amount needed for many years and it has worked well, hopefully I can do the same with Pyrocat.

[IanG]

Yes you mix just what you need before use with Pyrocat.

Ian

[Gem Singer]

LuisR,

I suggest that you get Pyrocat-HD in glycol from the Photo Formulary. It has a much longer shelf life.

Stock solution comes in two parts. You merely mix one part A with one part B and one hundred parts water to make a working solution.

(ie: 10ml A+ 10ml B + 1000ml water).

Once mixed, the working solution begins to oxidize. Discard after use.

The instructions are included in the package.

[Steven Nestler]

I've been using Pyro with Photoflo for years; no problem.

[D. Bryant]

I ran across information that states not to use Photo-Flo or similar chemicals on Pyro processed films as it will remove the stain. Where I live we have hard well water so not using Photo-Flo will result in water spotting on film. In addition, the PF instructions talk about using a Pyro after bath (meaning after fixing). My understanding was that after developing in Pyro and fixing in PF's TF-4 alkali fixer the film is just washed in water for about 45min. It is also stated that using TF-4 does not require a hypo clearing agent. Can the use of a hypo clearing agent speed up the wash process, and will using this chemical also wash away the Pyro stain? Thanks for your informed comments.

No photo-flo for pyro - Rubbish! And you don't have to use non alkaline fixer either and standard stop bath is fine also. No final soak in used developer and you can use hypo-clearing agent.

Pyro should be mixed immediately prior to development and as Mr. Singer points out the gycol based version is preferred for maximum shelf life.

[LuisR]

Thanks again to all for your valuable info!!!

[LuisR]

While I did see the development time charts in King's article I am curious to what development times for FP4+, PanF+, and Acros 100 in 35mm, 120, and 4x5 others use successfully. Thanks again.