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  1. #31

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    Quote Originally Posted by steve simmons View Post
    Let's try and correct the record.

    Staining developers are an asset for both VC and graded papers. The yellow-yellow green - orange brown stain with PMK retards blue and green light. The stain with PMK is proportional to the silver density. VC papers are sensitive to both blue and green light and graded papers are sensitive to blue light. The color of the stain retards the transmission of blue and green light and thus is effective for both types of papers.

    Shadows with PMK are not muddy if the proper exposure is given to the negative. You should always test for your personal EI - however you do the testing you should aim for a zone 1 density of .1 above fb+f.

    I did a test a few years ago with PMK and Pyrocat. I tested for EI and dev time for a vc paper with no filter - approx the same as a #2 filter. I then shot side by side comparisons, processed the film and made direct scans of the negatives. The PMK negative had much better high value separation. I would have been happy to change developers if the Pyrocat gave me better tonal separation up and down the scale. I did not feel it did.

    If you have not read The Book of Pyro by Gordon Hutchings I would strongly recommend doing so. It is the most definitive and comprehensive work on staining develpers and how they work. You can get a copy form Bostick and Sullivan or the Photographer's Formulary. Gordon will also be doing a workshop and a presentation on staining developers at foto3.


    steve simmons
    www.viewcamera.com
    Steve, Just wanting to make sure I understand your statements.

    Did you base your opinion of high value separation on digital scans of your PMK and Pyrocat developed negatives?

    If so, what were the separation measurand(s) you used? What did you use as an experimental control?
    Tom Hoskinson
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    Everything is analog - even digital :D

  2. #32

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    Steve, Just wanting to make sure I understand your statements.

    Did you base your opinion of high value separation on digital scans of your PMK and Pyrocat developed negatives?

    Yes.

    If so, what were the separation measurand(s) you used? What did you use as an experimental control?


    measurand(s)

    ??????????????????


    I compared the Pyrocat and PMK negs against each other.

    It is not really important, IMHO, which formula you use. The point of my post was to state that there are advanatges for both VC and graded papers when using a staining developer where the stain is proportional to the silver density as it is with both PMK and Pyrocat.

    steve

  3. #33

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    Quote Originally Posted by lee View Post
    Isn't it true that when one substitutes various chemicals in a formula, you are really formulating another developer? Is the pyrocat hd still pyrocat hd if you substitute ANY of the chems for another? Isn't that what happened when Sandy King introduced the various changes in the original Pyrocat HD?

    lee\c
    I will comment on this since it involves only Pyrocat.

    Yes, I agree with Lee. Any change one makes to a formula may have intended and unintended consequences. There is a family similarity between the various developers in the Pyrocat family, which include Pyrocat-HD, Pyrocat-MC (which are offered in commercial kits) and also Pyrocat-PC, which must be mixed from scratch at this time. However, objective testing would show some differences in characteristics between these formulas which might favor one or the other with a given set of conditions.

    To consider how significant the changes might be, just realize that merely increasing the amount of sodium sulfite in the Pryrocat-HD formula from 10 grams to 40 grams per liter of Stock A would make the formula non-staining.


    Sandy King
    Last edited by sanking; 11-30-2007 at 08:05 PM. Click to view previous post history.

  4. #34
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    Quote Originally Posted by leicam5 View Post
    So, 133 gr. of Pyrocat instead of 100 gr. of pyrogallol will do well too?

    Philippe
    What would you dissolve it in? I have a hard enough time dissolving 100 g pyrocatechin in a liter of propylene glycol. The ratios are about equal in activity given all else the same. We're already only using 20 ml of stock to make a liter of ordinary working solution, and 10 or less for stand development. BTW, the abbreviation "gr" means grains, of which there are about 15.3 to the gram.

    MY only purpose in exchanging the two agents was to change the color of the stain, and to show that it can be done using the developing strategy, so to speak, of Sandy King with pyrogallol as the agent. If you want to try catechol in place of pyrogallol using the strategy of Gordon Hutchings, I can't tell you if it will work because I haven't tried it. I don't have catechol on hand, so you will have to try it yourself. I could try it with hydroquinone, which we know can make a good developer with Metol, sulfite and a little borax, and also with Metol, ascorbic acid and borax, but whether or not either it or catechol will stain at the pH of PMK, I do not know. Hydroquinone stain is different from either catechol or pyrogallol.

    I think you could get the same effect from Pyrocat MC by using more of the A solution and TEA or the PMK Kodalk solution as B. That I can try because I have some Pyrocat MC on hand,
    Gadget Gainer

  5. #35

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    Quote Originally Posted by steve simmons View Post
    Let's try and correct the record.

    Staining developers are an asset for both VC and graded papers. The yellow-yellow green - orange brown stain with PMK retards blue and green light. The stain with PMK is proportional to the silver density. VC papers are sensitive to both blue and green light and graded papers are sensitive to blue light. The color of the stain retards the transmission of blue and green light and thus is effective for both types of papers.

    Shadows with PMK are not muddy if the proper exposure is given to the negative. You should always test for your personal EI - however you do the testing you should aim for a zone 1 density of .1 above fb+f.

    I did a test a few years ago with PMK and Pyrocat. I tested for EI and dev time for a vc paper with no filter - approx the same as a #2 filter. I then shot side by side comparisons, processed the film and made direct scans of the negatives. The PMK negative had much better high value separation. I would have been happy to change developers if the Pyrocat gave me better tonal separation up and down the scale. I did not feel it did.

    If you have not read The Book of Pyro by Gordon Hutchings I would strongly recommend doing so. It is the most definitive and comprehensive work on staining develpers and how they work. You can get a copy form Bostick and Sullivan or the Photographer's Formulary. Gordon will also be doing a workshop and a presentation on staining developers at foto3.


    steve simmons
    www.viewcamera.com
    Can you please confirm that your comparisons were done using scans of negatives and NOT prints to paper direct from the negatives.

  6. #36

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    Quote Originally Posted by sanking View Post
    Given that the thread title was "PMK versus Pyrocat-HD" I decided it best to not make any substantive comment comparing the two formulas. To the extent possible I would like to avoid entanglement in any more pyro wars, which I put more or less in the category of bad wine That is, if I never have any more of it in this lifetime I have already had enough for this life, and for all eternity.

    Sandy King
    Hi Sandy,
    I have witnessed a number of these pyro wars and I can hardly blame you for staying away. It's unfortunate and is a loss for the rest of us.
    Emancipate yourselves from mental slavery;None but ourselves can free our minds. - Bob Marley

  7. #37

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    Measurand

    Quote Originally Posted by steve simmons View Post
    Steve, Just wanting to make sure I understand your statements.

    Did you base your opinion of high value separation on digital scans of your PMK and Pyrocat developed negatives?

    Yes.

    If so, what were the separation measurand(s) you used? What did you use as an experimental control?


    measurand(s)

    ??????????????????


    I compared the Pyrocat and PMK negs against each other.

    It is not really important, IMHO, which formula you use. The point of my post was to state that there are advanatges for both VC and graded papers when using a staining developer where the stain is proportional to the silver density as it is with both PMK and Pyrocat.

    steve
    Thanks, Steve.

    Measurand: A measurand is a physical parameter being quantified by measurement.

    One can visually (and via reflection densitometry) compare prints made with PMK, Pyrocat and D-76 developed negatives contact printed on Silver Chloride paper, Pt paper, and/or PtPd paper.
    Tom Hoskinson
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    Everything is analog - even digital :D

  8. #38
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    We have in general been discussing here two different strategies of staining film development and at least two different spectra of stains. Anyone who thinks we are going to find one best strategy and/or one best color is mistaken. My hope was to show that either strategy or either stain color can be combined to make at least 4 different developers which can serve at least 4 different purposes.

    We know that the strategy involving high dilution with relatively high pH but low buffering capacity can be used to stain with either pyrogallol or catechol. Development by such solutions is noted for high resolution and sharpness by use of standing development.

    Reasonably high dilution with lower pH but greater buffering has somewhat different aims which have been successfully achieved by PMK using pyrogallol with sodium metaborate as alkali.

    I see no need for any kind of war. It's like deciding whether a cook must use only salt or pepper. Once the choice to use salt is made, pepper must never again be used.

    If I can keep a bottle of a mixture of catechol, p-aminophenol and ascorbic acid in propylene glycol and another of a mixture of pyrogallol, metol and ascorbic acid, and a bottle of triethanolamine or Kodalk solution and a bottle of 75% K2CO3 and have my choice of stain color and other image qualities, why should I not? And if I don't want stain, I can add some sulfite. I could clear out all but 4 or 5 of the myriad of bottles I have with different developers that must be periodically pitched anyway and still have everything I have now.
    Gadget Gainer

  9. #39
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    I should have pointed out that the most probable cause of a general stain in any staining developer is base fog. The developer is not smart enough to know which is image silver and which is base fog. To prove me wrong, fix a piece of unexposed film, wash it, and try to develop a stain on it with any staining developer. Now develop a piece of unexposed film in a non-staining developer, fix it, wash it and try to develop a stain in its fog silver with a staining developer. Now develop a piece of unexposed film in a staining developer and see if you get a base stain. These test strips should give you a clue as to how to prevent the overall stain.
    Gadget Gainer

  10. #40
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    Quote Originally Posted by gainer View Post
    What would you dissolve it in? I have a hard enough time dissolving 100 g pyrocatechin in a liter of propylene glycol. The ratios are about equal in activity given all else the same. We're already only using 20 ml of stock to make a liter of ordinary working solution, and 10 or less for stand development. BTW, the abbreviation "gr" means grains, of which there are about 15.3 to the gram.

    MY only purpose in exchanging the two agents was to change the color of the stain, and to show that it can be done using the developing strategy, so to speak, of Sandy King with pyrogallol as the agent. If you want to try catechol in place of pyrogallol using the strategy of Gordon Hutchings, I can't tell you if it will work because I haven't tried it. I don't have catechol on hand, so you will have to try it yourself. I could try it with hydroquinone, which we know can make a good developer with Metol, sulfite and a little borax, and also with Metol, ascorbic acid and borax, but whether or not either it or catechol will stain at the pH of PMK, I do not know. Hydroquinone stain is different from either catechol or pyrogallol.

    I think you could get the same effect from Pyrocat MC by using more of the A solution and TEA or the PMK Kodalk solution as B. That I can try because I have some Pyrocat MC on hand,
    Dear Mr Gainer,

    Forgive me my ignorance as well as the 'metric confusion' I might have provoked.

    I was just considering the fact that Pyrogallol is, at my supplier, about 3x more expensive than Pyrocatechol.
    And, I am still looking for a good and workable paper developer based on Pyrocatechol (+ Phenidone and Vit-C) and no Metol nor Hydrochinon to which I seem to be allergic. In my rather idle search, all the formula's I found, till now, were based on Pyrogallol, and the one, with Pyrocat, hardly lasted for a few hours in the open dish, but the image colour was precisely what I was looking for, a pity.

    But, for film, Sandy King's Pyrocat HD (mixed in de-mineralised water) is my number one, for 3/4 of the job's, the rest I reserve for Rodinal ( + borax, as you very well suggested).

    And Yes, grams, annotated in short, is g (All tough 'Imperial measure users' tend to write gm). But, apparently, we are not the only ones struggling with this ( see : CNN - NASA's metric confusion caused Mars orbiter loss - September 30, 1999 ).

    Philippe
    "...If you can not stand the rustle of the leafs, then do not go in to the woods..."
    (freely translated quote by Guido Gezelle)

    PS: English is only my third language, please do forgive me my sloppy grammar...

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