pyrocat and x-tol- the midtone muddle

Discussion in 'B&W: Film, Paper, Chemistry' started by Mike Lyons, Nov 30, 2004.

  1. Mike Lyons

    Mike Lyons Member

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    HI to all. I use HP-5 and FP-4 in 4x5 and Delta 100 & 400 in 120RF. Recently I have been trying Pyrocat-hd (and getting use to the "thin" negs) as a change from my usual X-T0l and have been getting good results. It's also considerably cheaper mixing from scratch in Australia rather than the cost of X-Tol. Some threads and articles have commented on poor midtone separation in the Pyrocat as opposed to the X-Tol, but as yet I am not convinced. Any comments from those who have used both? Anywhere that I can see some film developer curves of the two with the films that I use? I suppose the obvious answer is to do identical shots then developsheets in each then print as close to identical then............."suck it and see" as the expression goes.
    Regards- Mike
     
  2. jim appleyard

    jim appleyard Member

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    "Suck it and see"??? Oh my!
     
  3. Donald Miller

    Donald Miller Member

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    There are a lot of other factors that should be considered in midtone separation. Among those are film characteristic curve, paper characteristic curve, film exposure, film density range, contrast grade at which the print is printed.
     
  4. fhovie

    fhovie Subscriber

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    I use both Pyrocat and Xtol (Mytol) and find that the big difference is in accutance and highlights. I use home brew MYTOL which is jusl like XTOL in performance for RF and find the grain to be very tight and I am very pleased with it - much better than D76, D23 or MicrodolX. In LF where I contact print or enlarge only a few times, I use Pyrodat for its tanning and staining benefits. So for LF I use Pyrocat and for RF I use Mytol.
     
  5. Eric Rose

    Eric Rose Subscriber

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    My PryoCat-HD negs are not thin and my midtones are wonderful. Just as wonderful as the other ends too. I just printed a minicam neg of a scene taken in Nicaragua of a volcano. The tones ranged from black lava to bleached white rocks to foreboding (sp) sky. On top of the hill was a cross with vultures on it. The print on Ilford FB (yes Les I used FB, see I'm not so lazy LOL) has wonderful detail, tremendous tonal range and a wonderful luminous quality.
     
  6. sanking

    sanking Member

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    I am not sure where the idea started that Pyrocat-HD negatives should look thin. Perhaps someone made an analogy with PMK based on something Gordon Hutchins said the The Book of Pyro. I don't believe that I have every suggested this, and if I did it was a mistake.

    Pyrocat-HD negatives have a brownish stain that on first glance looks very neutral. In fact, many people on first using Pyrocat-HD complain that there is no stain, probably because their standard of comparison is the very heavy greenish stain produced by PMK. However, the key to properly exposed and developed Pyrocat-HD negatives is that they should look very much like negatives processed in traditional non-staining developers. It is only when you measure the negatives with a densitometer in blue or UV mode that you can appreciate the impact of the stain on actual printing density.

    Sandy King
     
  7. Doug Bennett

    Doug Bennett Member

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    Mike,

    Hope I'm not thread-jacking here.

    I've just received my first batch of Pyrocat-HD. Maybe the best advice I've read as to starting times is to take PMK times and reduce 30%. Do you all find this to be a reasonable method?

    Doug
     
  8. sanking

    sanking Member

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    I should add a note or two for clarification.

    For printing on VC silver papers a good rule of thumb for converting development times from PMK 1:2:100 development to Pyrocat 1:1:100 is to reduce the times provided by Gordon Hutchins in The Book of Pyro by about 20-30%.

    Virtually all of the development times that I have personally given for Pyrocat-HD have been for printing on graded silver papers (including AZO #2) and it is my experience that these times need to be increased by about 25% for VC papers.

    For printing with UV sensitive processes one would need to reduce the PMK 1:2:100 time even more, say about 40%, to develop with Pyrocat-HD 1:1:100. This is due to the fact that the brown stain of Pyrocat negatives provides much greater actinic filtration than the green PMK stain.

    Sandy
     
  9. Tom Stanworth

    Tom Stanworth Member

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    I know where I have seen many references to thin looking negs...the late Barry Thornton stated repeatedly that Dixactol and Exactol negs would look thin to the eye, but would print as if they possessed greater density. He argued that as the silver was less developed than in normally developed negs, in conjunction with the masking effect of the stain, this meant fine grain.

    My own experiences were that I struggled to get anything other than thin negs which printed (on VC) with very low contrast with the times suggested by him (I had to use at least grade 3.5-4 for starters). When I increased dev time (probably a good 25%), I got better contrast, better looking prints, but with Dixactol, the grain became shocking with many fims. Exactol Lux was far better in this regard, tho dixactol was great with 5x4 Fuji Acros. I found that effective film speed was surprisingly good (approx 2/3 stop more than Pyrocat HD when normal agitation used for both). I found that where a neg was thin in the shadows, it printed far better than a conventional neg would have, but I needed more development to seperate the mid tones and actually give me some decent highliights. That said, the highlight areas on good negs were still far less dense than conventional negs.

    In summary, I have found that flat negs always print flat, whether Thornton devs were used or not. Thos negs of mine that print well still show good seperation in the neg, albeit with slighltly less density than conventional negs. As Pyrocat HD negs are the same colour as those from Exatol/Dixactol, I cannot see there being a real difference. (I have yet to print my pyrocat negs as my darkroom is out of action for now).

    Tom
     
  10. Doug Bennett

    Doug Bennett Member

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    So, for graded papers, Pyrocat HD at about 50% of PMK times?

    I'm planning to shoot a couple of rolls of Classic 400 today and give it a try. Contrary to Tom, I'm hoping to see thin negs. On my condenser enlarger, a Beseler 23CII, thin is much better than thick. I just shot a bunch of Efke 100 while down in New Orleans, developed in Rodinal 1:50. The negatives look beautiful, but prints have that "chalk and soot" look that, in my experience, is a sign of too much density.
     
  11. sanking

    sanking Member

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    For graded papers it would be best use the times that I have provided in various places because they are keyed to graded papers. Virtually all times you will find for PMK are for VC papers and I don't have a method for matching these times back to graded papers with Pyrocat-HD. Basically I think that trying to do so is just to round about to provide accurate information.

    I am about out the door as I write this but if you can wait I will send you some recommnded times for both Classic 400 and Efke 100 later this evening. Just let me know how you plan to print, i.e. regular silver papers (and graded or VC), AZO or alternative?

    Sandy
     
    Last edited by a moderator: Dec 4, 2004
  12. Eric Rose

    Eric Rose Subscriber

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    Sandy:

    Does this mean if we use VC papers we should just go ahead and use the same times as PMK for neg development?
     
  13. sanking

    sanking Member

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    No, I did not mean to imply that. If you are sure that the PMK times you have are for VC papers then about 70-80% of that time would be a good starting point for Pyrocat.

    Sandy
     
  14. skahde

    skahde Member

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    Does this imply that average gradients for VC papers should be measured with white light rather than blue light as has been recommended for graded. When I develope to a gradient of 0,57 judged by blue light I have to enlarge on about grad 3,5 using Agfa MCC vs. Ilford Galerie grade 2.

    Would make sense to me and explain the difference I see quite nicely.

    Stefan
     
  15. sanking

    sanking Member

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    Stefan,

    You have hit on something very important. Years ago Phil Davis did some tests with PMK and determined that there was no single mode on the densitometer that gives a reading that exactly indicates printing density of VC papers. With graded papers, including AZO, a reading in Blue mode with a color densitometer will tell you almost exactly how a negative will print. Same is true of a UV reading for alternative processes that are UV sensitive. But a reading in Blue mode will not accurately indicate how a negative will print on a VC paper because these papers are also sensitive to green light. What Davis determined was that the best reading would be one about 2/3 of the way from the Blue reading toward the Green.

    If that were not enough to make us scratch our heads there are the added complications in that, 1) the actual spectral sensitivity of different VC papers may be different, and 2) the color and intensity of the stain varies considerably according to film, even when dealing with only Pyrocat-HD.

    But the bottom line is that a negative developed in a staining developer usually needs to be developed to a slightly higher CI for VC papes than for graded papers.

    Sandy King
     
    Last edited by a moderator: Dec 5, 2004