Article on Pyro Developers

[sanking]

I have a new article on Pyro developers now up at http://unblinkingeye.com/Articles/PCat/pcat.html

Welcome any comments, corrections, suggestions, etc.

[David A. Goldfarb]

Very informative and detailed article. The only additional thing that might be interesting, if it could be done successfully for presentation on the web, would be some illustrations from negatives and/or prints showing the effects of different pyro formulas, maybe with a standard developer or two like D-76 or HC-110 in there for comparison. I realize that there are resources like this out there in back issues of _View Camera_ and such, but it seems like this would fit naturally here.

[Francesco]

Well done Sandy. Just printing out a hard copy right now. I have a question concerning two points:

1. In this article you recommed a presoak in distilled water of 5 min. in BTZS tubes. In another you recommended 2 to 3 mins. Any real difference? (BTW, I place the distilled water in the tube caps and then shake it well for about 2 or 3 mins).

2. You recommed the use of a stop bath in the article. How long time should the film stay in the bath? You have also stated elsewhere that 1 minute in water was good enough if the fixer used is TF-4. Is this still the case? (By the way, I put the stop bath in extra BTZS tube caps and agitate slightly for about 30 seconds before I let the film lie in plain water for 1 minute. What do you think?).

Once again, congratulations on a well-written and generously-given article.

[Alex Hawley]

Thanks Sandy for this excellent article. Comprehensive and well-written. The best overall reference I've seen concerning all of the pyro developers. I'm adding it my reference notebook..

[Ole]

I'll just add my praise and appreciation to those above.

Thanks a lot!

[sanking]

The only additional thing that might be interesting, if it could be done successfully for presentation on the web, would be some illustrations from negatives and/or prints showing the effects of different pyro formulas, maybe with a standard developer or two like D-76 or HC-110 in there for comparison. I realize that there are resources like this out there in back issues of _View Camera_ and such, but it seems like this would fit naturally here.

David,

Actually, I am not sure that there are any comparison illustrations of this type in back issues of View Camera. I have not seen them.

However, showing these differences is definitely something that I have thought about doing. Any ideas about the methodology for doing this in an effective way for showing on the web?

Sandy

[sanking]

Well done Sandy.

1. In this article you recommed a presoak in distilled water of 5 min. in BTZS tubes. In another you recommended 2 to 3 mins. Any real difference? (BTW, I place the distilled water in the tube caps and then shake it well for about 2 or 3 mins).

2. You recommed the use of a stop bath in the article. How long time should the film stay in the bath? You have also stated elsewhere that 1 minute in water was good enough if the fixer used is TF-4. Is this still the case? (By the way, I put the stop bath in extra BTZS tube caps and agitate slightly for about 30 seconds before I let the film lie in plain water for 1 minute. What do you think?).

Francesco,

I use a five minute pre-soak time because it adds to consistency of results when testing various films, especialy with short development times. Rate of develoment depends on induction and transfer of chemicals into and out of the gelatin emulsion, and the rate varies among films. At five minutes they all perform about the same. For any given film a 2-3 minutes pre-soak should be fine.

About the stop bath, when using a diluted acetic acid bath the film only needs to stay in the bath for 10-15 seconds. If using water, change the water 4-5 times over a period of about a minute.

[Donald Miller]

Sandy, Thanks for your efforts in behalf of the photographic community. This article is both comprehensive and concise.

[doughowk]

Great article. Hope to see this level of quality for articles in future APUG mag. I'll be trying Pyro HD this weekend for negs to be printed on Azo, and will use this info as a guide.

[jbrodkey]

Terrific article. I printed it out and would like to try Pyrocat instead of the Rollo Pyro which I now use. However Sandy says you should mix the stock solutions under a hood or outside.
I live in an apartment house - no hood and hard to work outside. Photographer's Formulary
only supplies the powder although they do provide the stock solutions for several other Pyro developers. Why don't they supply Pyrocat in liquid form. Is there some reason for only supplying the powder?