Pyrocat HD and Tmy

Discussion in 'B&W: Film, Paper, Chemistry' started by Brian Bullen, Jun 26, 2004.

  1. Brian Bullen

    Brian Bullen Member

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    Hello everyone. I've been wanting to try Pyrocat and 4x5 Tmax 400 but I can only find development times for use with tubes. I pretty much do all my developing in tanks and sometimes trays does anyone have a good start time for tanks with normal agitation?
    I've read that TMY in Pyrocat has an effective film speed slighty higher than 400, is this true or should I start my tests at around 400.
    Also I will be using a cold light enlarger for contact prints (switching to 8x10 once I finish the test) Thanks for your help.
     
  2. Tom Hoskinson

    Tom Hoskinson Member

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    My starting point for Kodak TMY 400, rated at EFS 400 is Pyrocat diluted 2:2:100, semi-stand developed in a tray (a slosher) for 16.5 minutes at 71 F. Semi-stand agitation: 20 seconds of gentle agitation intially, followed by 5 seconds of gentle agitation at the 8 minute (half-way) point. For minimal agitation (5 seconds gentle agitation per minute) reduce the development time by 30%.

    I have plotted the D Log E curve for the semi-stand condition I described if you are interested.
     
  3. sanking

    sanking Member

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    Tom,

    I would be interested in looking at your plot of Tmax 400 and Pyrocat-HD with these conditions. My own semi-stand development of Tmax 400 is based on a dilution of 1:1:150 so I would be very interested in comparing curves.

    Sandy
     
  4. Tom Hoskinson

    Tom Hoskinson Member

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    Sandy, the plot and data is in a MS Excel file in my lab computer. I can email it Monday. I used a Macbeth TD 504 color densitometer and recorded the "all" channel and the blue channel data.
     
  5. Brian Bullen

    Brian Bullen Member

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    Tom, thanks. I also would be interested in the plot of Tmy for semi stand agitation. Any info I can get on this is greatly appreciated.
     
  6. Tom Hoskinson

    Tom Hoskinson Member

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    I sent the Excel file to you and Sandy as an email attachment. I suppose I could also have attached it to this message as a PDF file.
     
  7. Tom Hoskinson

    Tom Hoskinson Member

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    I have attached a PDF version of my TMY/Pyrocat Excel File (I hope).
     

    Attached Files:

  8. Brian Bullen

    Brian Bullen Member

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    Thanks again Tom, this is very helpful. I ordered some pyrocat today and can't wait to start shooting.
     
  9. sanking

    sanking Member

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    Thanks. For your interest I am attaching a family of curves of TMY in Pyrocat-HD 1:1:150 and developed with extreme minimal agitation. The meaning of the numbers on each line are as follows: 1) Development time (multiply by 10X), 2) Effective Film Speed, 3) CI or contrast index, and 4) SBR, where 7 is considered normal and equivalent to N.

    The SBR values as given are based on a desired negative density range of 1.55 for printing on AZO #2 papers, and the readings were made with the blue channel of a color densitometer.

    Sandy King
     

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  10. Jorge

    Jorge Inactive

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    Sandy, I tried the semi stand development and your curves confirm my first impression. It seems that for extended development and even for the "normal" development the b+f is quite high. Has this been a problem with your pt/pd printing and lenght of exposures?
     
  11. sanking

    sanking Member

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    Yes, there is quite a bit more general stain created with this type of development and it does increase printing time significantly with UV processes. But the curious thing is that the used developer is perfectly clear, even after as much as 1.5 hours of development. Normally we figure that the creaton of general stain with pyro developers results from oxidation which causes it to turn browner and browner with time. But in this case the reason for the increase in general stain would appear to be something other than oxidation.

    Sandy
     
  12. TN98

    TN98 Member

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    I've read somewhere in APUG that the increase part A would lower BF (1.5:1:150), isn't it?
    I've plan to test the TMY 8x10 for Pt/Pd print with Pyrocat HD semi-stand with BTZS tube. Which dilution and set of time should I use to run on winplotter.

    Thanks,
    TN
     
  13. sanking

    sanking Member

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    I use a 1.5:1:200 dilution for TMY and extreme minimal agitation (four agitation periods).

    Try about 30-40 minutes with this dilution at 70F if you plan to print on VC silver papers. Agitate very vigorously at the beginning for about 1.5 minutes, then gently for 15 seconds for the other agitation periods.

    Sandy King
     
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  15. TN98

    TN98 Member

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    What is the time for Alternative Process like Pt/Pd?
     
  16. cahayapemburu

    cahayapemburu Member

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    That's a lot of non-image density; whether it's fog or general stain, but it shouldn't be a major problem for rollfilm shooters developing for density ranges around 1.0 to print on middle grades of paper. I don't think Sandy's or Tom's developing data is intended for silver papers, and I don't know how they tolerate so much non-image density for Alt processes.
     
  17. sanking

    sanking Member

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    Where did you get the data for B+F? My own B+F for the times specified was .17 at 30 minutes to .25 for 40 minutes. And the absolute B+F of the film, with development of five minutes in a non-staining developer, was .12, so we only added log .05 with 30 minutes of development, which seems very low to me.

    The developing data I gave was indeed intended for silver printing, specifically on VC papers with diffusion type light source. For that type of printing my opinion is that you need a negative with a CI of about .55-.65, which gives a DR of about 1.35 with a staining developer. With TMY I get this CI with Pyrocat-HD and the 1.5:1:200 dilution with between 30-40 minutes of development, with the agitation type specified, i.e. Extreme Minimal.

    The above assumes analysis by blue mode densitometry.

    Sandy King
     
  18. sanking

    sanking Member

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    Turns out that you need about the same time for pt/pd. A DR of about 1.35 by blue mode turns out to be a DR of about 1.85 by UV mode, and that works fine for printing with many alternative processes, including pt/pd. You would need a bit more for printing with albumen, salted paper, pure palladium or VDB, up to log 2.5.

    Sandy King
     
  19. Tom Hoskinson

    Tom Hoskinson Member

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    cahayapemburu, You wrote: That's a lot of non-image density; whether it's fog or general stain.

    What data did you base that statement on? It is not consistent with the D log E curves I posted.
     
  20. sanking

    sanking Member

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    Tom,

    In reading back through the thread I think cahayapemburu must have gotten those values from the data in a family of curves I posted several years ago, in July 2004 to be exact. I was confused because I thought he was referencing one of the new messages.

    The B+F values are pretty high because, 1) the tests were made with TMY film that was fairly old, with a fair amount of B+F from aging, and 2) the readings were based on UV analysis, not Blue as I indicated in the messages that accompanied the image file.

    And yes, as Jorge indicated back then, and I recognized, B+F times get very high with UV mode when you develop with a staining developer for very high CI. And especially with aged fillms. The times get very long even with non-staining developers and fresh film.

    Sandy
     
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  21. cahayapemburu

    cahayapemburu Member

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    I was commenting on the data posted in this thread; maybe it's the old data based on outdated film? I won't ask why one would publish that kind of data; I'm sure Sandy has his reasons, but what I do wonder is why Sandy feels VC papers require such high density ranges? Scaling negatives for a paper grade between 2 and 3 is widely recommended and commonly practiced for maximum flexibility in printing, and a thin negative consistent with optimum sharpness and minimum grain. These negatives should have a density range around 1.0. Keeping in mind these values are logarithmic, 1.65 is much, much more dense than 1.0; what is gained by so much added density?
     
  22. sanking

    sanking Member

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    I recommend this density for printing stained negatives on VC papers. It is based on the fact that if you want the highlight compression that is available with the stain, due to the blue and green sensitive parts of the emulsion, you should develop to a high contrast and then control contrast with the low number filters. If you develop to a lower CI and use the higher number VC filters to control contrast, you lose the effects of highlight compressions offered by staining developers. And highlight compression with the combination of staining developers and VC papers is highly unique.

    If your goal is to print both VC and graded silver papers with traditional non-stained negatives, then the approach you advocate, developing to a lower CI that would print about the same on a graded silver paper or a #2 VC paper, would be the best approach.

    It depends on what you want to achieve, and how you want to go about it.

    If you want to read more about the issue in more detail I recommend a few threads that appeared on the LF forum in January of 2007. I personally don't have any desire to discuss the issue any longer since I am not involved with printing VC papers. However, I still stand behind the opinions expressed in these threads.

    I will also add that some recommendations made by Mr. Gordon Hutchings for the density to shoot for with PMK at Zone VIII, about log 1.5 as I recall, appears to agree with my advice on the matter.

    http://www.largeformatphotography.info/forum/showthread.php?t=16066

    http://www.largeformatphotography.info/forum/showthread.php?t=22261


    http://www.largeformatphotography.info/forum/showthread.php?t=22188

    http://www.largeformatphotography.info/forum/showthread.php?t=22215



    Sandy
     
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  23. cahayapemburu

    cahayapemburu Member

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    Developing to a higher than normal contrast in order to control highlights is not an approach I would advocate, whether one is using a staining developer, or not. When photographing a scene with a long illuminance range, presumably a circumstance in which one would benefit from highlight compression, it is counterproductive to develop to a higher than normal contrast. These overdeveloped negatives will suffer reduced sharpness and increased grain. It is a better approach, in my opinion, to control highlight density in film development, and particularly when photographing scenes of extended illuminance range, and print on a middle grade of paper, or the equivalent VC paper exposure scale. This allows maximum flexibility in printing, which is important for rollfilm shooters who develop all frames to a common contrast. LF negs are far more tolerant of overdevelopment, and a better format for utilizing the special stain/VC relationship in the extreme way Sandy advocates.
     
  24. sanking

    sanking Member

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    First, there is no "normal" contrast. One develops according to the situation, negative and developer, and type of printing anticipated.

    Second, I have no idea how you work, but I expose and develop rollfilm (120 and 220 film) just as I expose and develop LF film. When the film leaves the camera I note what type of development is required for the exposures, either N+ or N-. If the roll contains scenes of different contrast I identify the most important exposures on the roll and develop for that specific contrast. I never develop all MF rolls to a common contrast, and consider such practice unacceptable if optimum results are desired for the most important images on the roll.

    Sandy
     
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  25. cahayapemburu

    cahayapemburu Member

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    I seem to have touched a nerve; sorry.

    First, yes Sandy, there is "normal" contrast. Normal contrast is that which will match a negative exposed under normal lighting conditions, to a normal grade of printing paper. It is normal because a 7-stop scene illuminance range is considered normal, and a printing paper exposure scale of 1.0 is considered normal, and a negative is an intermediary between the two, and as such, a normal contrast value is indicated, and identified by every manufacturer of film. End of lesson.

    Second, I didn't write "..develop all rolls to a common contrast" , but "...develop all frames to a common contrast", and I think the distinction should be obvious. Semantics and misreadings aside, what remains is that it is not uncommon to have exposures made in various lighting conditions on a single roll, and no single development will be optimum for all exposures, so the flexibility afforded by VC paper should be optimized by developing to a contrast suitable for printing negatives exposed under normal lighting conditions on paper with an exposure scale of around 1.0. Besides, in your own post you recommend developing to "a high contrast", but if there's no normal contrast, then how can there be high contrast? You don't seem to hold yourself to the same semantic standards you demand of others. If, as you've written, you don't want to discuss this subject, then don't, but if you want to criticize my terminology, at least read my posts, and then go back and read your own before taking a superior stance.
     
  26. sanking

    sanking Member

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    Let me ask you this straight out. Are you Jay DeFehr?

    Or, are you acting in any way on behalf of Jay DeFehr?

    You sure sound a lot like him to me.

    If not, I simply told you how I exposed roll film. I really don't care how you do it. Just don't involve me any more in your discussions. I don't appreciate your attitude and wont' respond any more to your messages about photography.


    Sandy King
     
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