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  1. #1

    Join Date
    Feb 2008
    35mm RF

    Questions for Prescysol EF Users

    I thought that I would try Prescysol EF. Because I donít want to reinvent the wheel, I would like to ask some questions to this sage* group of erudite* darkroom practitioners of the ancient art of photographic alchemy.

    1. The times for agitation are presented fairly well in the Photographerís Formulary text. My question is whether itís best to develop a roll in a double reel tank with the upper reel empty and enough solution to cover the loaded reel only? Iíve used this empty-reel technique with other developers and it seems to promote very even development. The amount of air space could cause more oxidation of the solution and Iím concerned about the effect on Prescysol EF solution. Any tips for an agitation plan?

    2. The suggested starting time is 10.5 minutes for stand development. I imagine that there will be some final correction for my individual system. Have others found this to be a good ballpark estimate?

    3. Is the Photographerís Formulary text about full emulsion speed correct?

    4. The recommended dilution is 1:1:100. Have others tried different dilutions? Are there any advantages to adjusting to something like 1:1:50, 1:2:100, or 2:1:100?

    5. Does anyone use Prescysol EF for pushing? Digitaltruth Photo shows a 2 stop push with a standard developer is x2.25 the normal time and a compensating developer is x1.85 times normal time. Would Prescysol EF be classified as a compensating developer? If the suggested normal time is correct then this would be 19.5 minutes or 23.5 minutes (rounded to nearest .5 minutes). I have not seen very much on this aspect of Prescysol EF use.

    Thank you for your generous* time and gracious* responses to my lowly and unworthy inquiries.

    *Anything that helps me get needed information is OK by me.

  2. #2

    Join Date
    Feb 2006
    Oslo, Norway
    Multi Format
    I’m not a long time Prescysol EF user, but I bought a kit a few years ago in order to try a pyro developer.

    1. I would not worry about oxidation. If I remember correctly I used this method when developing a roll of 135 film and I encountered no problems. Nor have I had any ill effects from oxidation when using Pyrocat later on. I believe that Prescysol EF is a Pyrocatechin based developer and as such not that sensitive to aerial oxidation: http://unblinkingeye.com/Articles/PCat/pcat.html

    2. I tried this developer before I started to use a more thorough film testing regime. That said, I found the suggested developing time to be ok for medium speed films like fp4, exposed in normal contrast light, but a bit on the short side for high speed films like tri-x that had been exposed under similar conditions.

    3. With the same disclaimer as above, I got an EI close to box speed with medium speed films but not with high speed films.

    4. I only tried the 1+1+100 dilution. But based on my limited knowledge of Pyrocat I am convinced that you can use other dilutions successfully.

    5. I have not tried this either, but I would buy some Microphen or the like for use when pushing film.



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