Pyrocat dilutions

Discussion in 'B&W: Film, Paper, Chemistry' started by noseoil, Dec 18, 2007.

  1. noseoil

    noseoil Member

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    Ive been using pyrocat-hd for a couple of years now and have found it to be a great developer with good versatility, tonality, grain and generally fine results. My normal solution is 1:1:150 for most things, with the occasional semi-stand thrown in for good measure. It seems capable of decent results with many different films, traditional to tabular.

    I continue to hear about people who have "tweaked" the numbers by varying the concentration with respect to parts A & B. For example, some folks use it with 1: 1.5: 150 or 1.5 : 1: 200. I know that changing dilution and agitation can affect development and grain, but could someone explain how this change in dilution of the A & B parts affects development? Does it change the actual film's curve at all, or does it simply change development time?

    Thanks, a befuddled tim

    P.S. I'm interested in people who have actually done these experiments, not in the cousin of a step-brother whose milkman knew a guy whose uncle was working in....:confused:
     
  2. ChuckP

    ChuckP Subscriber

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    Tim,
    Hate to throw your question back at you but how did you end up with 1:1:150 instead of the "standard" 1:1:100?
     
  3. noseoil

    noseoil Member

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    Chuck, I use minimal agitation as this slows things down a bit. It really helps when doing films like Efke 25, which reacts too quickly for me with the standard dilution, almost a violent development. Since I liked the results, I've started doing more with it and other films. Efke 100 gives good results with nice edges and a bit faster film speed. It seems that minimal agitation allows the film to develop fully and slowly. Perhaps not for everyone, as it does take more time in the soup, but as an amateur, there isn't a problem for me and longer development times. best, tim
     
  4. c6h6o3

    c6h6o3 Member

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    I use a dilution of 1:0.6:120 or 1:0.6:150 using semi-stand development on the advice of Steve Sherman when I need extreme compensation (approx. N-5 development). Backing off on the B solution, which is the accelerator, reduces highlight development while allowing the shadows to develop fully.

    For normal negatives to be developed semi-stand I'll use 1:1:120.
     
  5. Shawn Dougherty

    Shawn Dougherty Member

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    I use 2:2:150 for my Delta 100 negs to print on graded paper. 1:1:100 negs were too thin, 2:2:100 negs seemed too dense.... 2:2:150 negs print just right. I have little to no understanding of what why or how, just that they look good.
     
  6. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    I think part A contains the normal developing agents, and part B is the 'activator'. I think you want to focus on varying the part B for various results. More of it should accelerate your development if I understand it correctly.
    I use 1+1+100 for my Tri-X, Foma 400, and some Agfa APX films at 16 minutes with reduced agitation (once every 3 minutes). For FP4+ I dilute more to 1+1+150 but keep the time constant. It works very well for me, and I have found no reason to experiment with it more.
    To vary the relationship between part A and part B to other than 50/50 - I have no experience. I think you need enough of part A to make sure you don't exhaust the developer, and enough of part B to accelerate the development to your liking.
    Someone with more profound knowledge will have to confirm this, however, as I am not generally interested in the scientific part of it.

    - Thomas
     
  7. climbabout

    climbabout Member

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    pyrocat dilution

    Tim -
    I arrived at 1.5/1/175 as my standard dilution. I

    can't tell you what it does to the curve, but I arrived at it by trial and error when I was fitting FP4+ to the paper I use. I mainly contact print on graded FB paper and this dilution gives me nicely developed highlights and full shadow detail. My normal development is what I guess you call extreme minimal or minimal agitation. Plus this gives me full(actually a little more than full) film speed. I rate my 8x10 fp4+ at 160, dilute at 1.5/1/175 and develop for 45min(70 degf) in a pvc tube - fully filled with solution. Agitate vigorously for the 1st minute, then 2 inversions at 15min, then 2 inversions at 30min. The tube stands on end between agitation cycles. I usually get a near perfect print at my standard proofing time with great edge contast on what is essentially a grade 2 paper. I develop the paper in DR. Beers at the #4 dilution - which allows me to vary the dilution both up or down in contrast up to 3/4 of a grade.
    I've compared negs of the same scene developed in a rotary jobo at a slow speed at 1:1:100 and the difference in edge contrast is remarkable. Altering the amount of restrainer (B) seems to keep the highlights where I like them. Sorry if I'm not more scientific - but I arrived at this based on what I see in the final print.
    I've simplified my life greatly by sticking to one film/one paper/and now 1 developer.

    Hope this helps.
    Tim
     
  8. Bruce Osgood

    Bruce Osgood Membership Council Council

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    I come from the point of view that Pyrocat HD was developed for use in a Jobo/roller system and was intended for constant agitation.

    My Jobo has one speed only and I had disappointing results with 1:1:100. Sandy suggested I try 1.3:1:100 to compensate for the "High" speed of the single speed Jobo. I did and it seemed to work but not to what I expected.

    I now use 2.6:2:100 and get what I think are good negatives. My films are FP4+ and HP5+. "Normal" times are about 10:00 minutes and I do use a pre wash.
     
  9. jim appleyard

    jim appleyard Member

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    Tim, I use 2+2+100. I can't fully answer your question, but at 1+1+100 the negs were thin.
     
  10. sanking

    sanking Member

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    Almost all developers, Pyrocat included, can be used with a wide variety of dilutions. My earliest recommendations were dilutions of 1:1:100 for silver papers and 2:2:100 for alternative processes, with either development in tray or tank with normal agitation, or development in Jobo or BTZS tubes with constant agitation. Development times given were based on rotary, so if developing in tanks and trays development should be increased by about 15-20%.

    Pyrocat also works well with stand and semi- stand development using very dilute solutions, say 1:1:200 - 400. As a result of a long exchange on the AZO forum, 1:1:150 was recommended for stand and semi-stand development. This requires much longer development time than either rotary or tray processing, both because of the weaker dilution and because of the reduced agitation.

    For most of my own work with both sheet film and roll film I personally use a type of development that I have called Extreme Minimal, that is, agitation for 1.5 minutes at the beginning, and then for ten seconds at the 1/4, 1/2 and 3/4 points of total development time. The dilution that I use is 1.5:1:200.
    The slight increase in the amount of A solution compared to 1:1:150 is meant to reduce B+F stain slightly with the very long development times I need for my alternative process negatives.

    Sandy Kiing
     
  11. noseoil

    noseoil Member

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    Sandy, do you think the change in A & B parts is affecting the development densities at differing tonal ranges in some of the above posts, or is it more a matter of dilutions and agitations? I understand why you have altered the A & B ratios for stain. tim
     
  12. sanking

    sanking Member

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    Tim,

    The slight increase in the amount of A solution serves to reduce oxidation, which in turn lowers B+F stain. Probably not significant if you are printing with silver processes.

    Sandy
     
  13. c6h6o3

    c6h6o3 Member

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    That's what I do. I've just been calling it something else. Interesting that your dilution is just about what I have been using.

    Do you vary the solution A to B ratio to yield greater contrast or to provide compensating development in extremely high SBR situations?
     
  14. sanking

    sanking Member

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    The primary reason that I vary the A to B ratio is to reduce B+F stain. Since I work with alternative processes my development times are much longer than for silver. Longer development times with any pryo developer results in greater oxidation and general stain. Increasing the amount of A relative to B reduces oxidation.

    As I mentioned earlier, this probably is not of any importance if you develop for silver printing, since development times are much shorter.

    Ordinarily I test for SBR with BTZS testing and adjust for subject brightness by varying the time of development rather than changing the dilution. However, there are times, say with extreme SBR conditions of -10 or more, when varyying the dilution may work better than a change in temperature.


    Sandy King
     
    Last edited by a moderator: Dec 19, 2007