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Thread: Pyro Stain bane

  1. #21

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    Quite correct! And this is why I have always emphasized that consistency of processing is critically important when using pyro purely because of the oxidation/stain variable. Many people are not consistent in their processing technique and therefore can't control the stain.

    Quote Originally Posted by Jarvman View Post
    Sheet film in trays, not much chance of controlling oxidation!

  2. #22

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    Quote Originally Posted by sanking View Post
    Diane,

    With some tubes and drums the film fits so tightly that if you load the film dry and then pre-soak and develop the the solutions will not fully reach the back (or base) of the film during processing because it is so tightly pressed against the inside of the tube/drum. If this happens it may be very difficult to remove the film after you finish processing.Sandy King
    ...Not to mention the vexing problem of uneven stain on the base side that sometimes shows up as slight lines of higher density where the negative touches the ridge of the cylinder (at least in processing 5x7 in a 3006). With the 3000 series tanks I know this to be the case when using PMK and rollo pyro, ABC and WD2D. I've yet to try Mr. King's formula in the Jobo and so do not know if his formula is dogged by this problem.

  3. #23

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    Quote Originally Posted by frotog View Post
    ...Not to mention the vexing problem of uneven stain on the base side that sometimes shows up as slight lines of higher density where the negative touches the ridge of the cylinder (at least in processing 5x7 in a 3006). With the 3000 series tanks I know this to be the case when using PMK and rollo pyro, ABC and WD2D. I've yet to try Mr. King's formula in the Jobo and so do not know if his formula is dogged by this problem.

    Uneven stain on the base side is a potential problem with any pyro staining developer if the base side does not get good solution flow during development. The issue is that many films have a clear gelatin coating on the base side that will stain in the same way that the emulsion side will stain, the purpose of which is to prevent excessive curl and/or to serve as a retouching base. If the base side does not get an even flow of developer this will show up as uneven staining. The severity of the problem is dependent on the thickness of the base coating as well as amount of stain. It may help to use a weaker dilution of the developer, or to mix the developer with a bit of tetrasodium EDTA, but in some cases you may have to switch to a non-staining developer to completely eliminate the problem.

    This type of stain is different from oxidation type stain that can be prevented by choice of developer or by processing technique. In the early days of PMK it was found that development in Jobo gave a very high general stain. One of the earliest solutions that worked to prevent this was dividing the developing solution into two parts and replacing with fresh solution at the half way point. Later it was found that adding small amounts of sulfite or ascorbic acid to the working solution would also reduce oxidation stain, though this will be accompanied by more energy, which requires shorter development times. The primary difference between PMK and Rollo Pyro (originally introduced by Harald Leban back in the late 1990s as ABC+) is that the latter contains ascorbic acid, along with a bit of bromide.

    Sandy King
    Last edited by sanking; 03-24-2010 at 06:43 PM. Click to view previous post history.

  4. #24

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    I'd recommend using non-pyro developer for the other negative until you get the hang of manipulating PMK.

    Keep oxidation to a minimum and very little after bath, if at all any. I usually add another 5, 10, or 15 seconds when I do use it. Stain intensifies in the wash.
    I brake for fixer!

  5. #25

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    Quote Originally Posted by sanking View Post
    Uneven stain on the base side is a potential problem with any pyro staining developer if the base side does not get good solution flow during development. The issue is that many films have a clear gelatin coating on the base side that will stain in the same way that the emulsion side will stain, the purpose of which is to prevent excessive curl and/or to serve as a retouching base. If the base side does not get an even flow of developer this will show up as uneven staining. The severity of the problem is dependent on the thickness of the base coating as well as amount of stain.

    Sandy King
    Thanks for this. This is consistent with my experience as I've noticed that the more careful I've been in thoroughly washing the base side down, the more consistent my overall stain. I've worked with the EDTA but did not like the results as much as straight pmk - reduced edge effects and a slightly more compressed neg. to my eyes. If flow over the base side of the neg. with staining developers is this critical why recommend using a jobo at all? The easiest path to clean pyro negatives for me has always been inversion with a full-to-the-brim combi-plan or patterson tank.

  6. #26

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    Quote Originally Posted by frotog View Post
    Thanks for this. This is consistent with my experience as I've noticed that the more careful I've been in thoroughly washing the base side down, the more consistent my overall stain. I've worked with the EDTA but did not like the results as much as straight pmk - reduced edge effects and a slightly more compressed neg. to my eyes. If flow over the base side of the neg. with staining developers is this critical why recommend using a jobo at all? The easiest path to clean pyro negatives for me has always been inversion with a full-to-the-brim combi-plan or patterson tank.
    That is an interesting comment about adding EDTA to PMK. I would have assumed some difference in result but would not have anticipated reduced edge effects.

    Good question about why Jobo at all, but not one I can address because I have never owned a Jobo. I personally prefer development methods that allow the use of minimal agitation because this seems to favor greater acutance.

    Sandy King

  7. #27

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    Quote Originally Posted by sanking View Post
    That is an interesting comment about adding EDTA to PMK. I would have assumed some difference in result but would not have anticipated reduced edge effects.

    Good question about why Jobo at all, but not one I can address because I have never owned a Jobo. I personally prefer development methods that allow the use of minimal agitation because this seems to favor greater acutance.

    Sandy King
    Sandy,

    I had thought you were an advocate of rotary processing?

    Tom

  8. #28

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    Quote Originally Posted by Tom Kershaw View Post
    Sandy,

    I had thought you were an advocate of rotary processing?

    Tom
    Tom,

    There are many good things about rotary processing in tubes or drums. It is economical (not much developer is needed), consistent, and gives very even development over the entire film. I use rotary processing (in BTZS type tubes) for film testing because it gives such even results, and I use rotary processing for developing ULF sheet film for convenience reasons (takes up much less space than tray processing).

    That said, development procedures that use minimal agitation schemes (stand, semi-stand, agitation every two or three minutes) will often give more acutance than rotary processing. So in most cases I develop medium format and LF up to 5X7 in tanks or full tubes with minimal agitation.

    Sandy King

  9. #29

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    Yes, the benefits of stand and semi-stand are good reasons not to use the jobo but beyond acutance it should be reiterated that the biggest problem with rotary processing is and always will be increased oxidation. Sure, there are all sorts of ways to deal with this, many of which have been touched on in this thread and I suppose they are "good enough". But the only way to totally eliminate the problems associated with the higher levels of oxidation is with a nitrogen gas blanket. Now that I use this technique with both staining developers and c41 I've come to regard the nitrogen tank and regulator as the component of rotary processing that Jobo forgot to include in their kit. In fact, nitrogen gas is a necessary component to bring the c41 development process in control to Kodak professional specs. Anyone who tells you otherwise has not done the control strips and the sensitometry.

  10. #30

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    Out of curiosity is it possible to eliminate pyro stain following processing/drying with a bath of sulfite?

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