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  1. #1

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    Barry Thornton's version of Perceptol............

    After finally getting his book "Edge of Darkness" and doing some enjoyable reading I noted a few things I'm curious about. One of those things is his "version of Perceptol" that he speaks about. Now, he doesn't disclose his Perceptol formula in the book and says he's working on it at the time of this writing. He speaks highly of Perceptol throughout his book and uses it for some of the pictures in the book itself. I'm just curious as to whether or not he ever disclosed "his version" of Perceptol???? Nice book, good reading, but I haven't really learned anything new. It's still nice to see/read how other people evolve and work. JW

  2. #2

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    Perhaps he was just scratch-mixing the formula which is often assumed to be Microdol (not x) and or Perceptol. Or maybe he was making small adjustments to the concentrations of the ingredients (the way he did with his versions of two-bath Metol-sulfite/alkali formulas).

    As is often the case in these kinds of books I'd suggest taking Thornton's chemistry with a grain of salt (so to speak).

  3. #3
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    Quote Originally Posted by Michael R 1974 View Post
    As is often the case in these kinds of books I'd suggest taking Thornton's chemistry with a grain of salt (so to speak).
    Why?
    Dan

    The simplest tools can be the hardest to master.

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    Quote Originally Posted by Pioneer View Post
    Why?
    I think he might just be using the "grain of salt" thing as humor since the homebrews for Microdol and Perceptol contain salt (NaCl), but I could be wrong. JW

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    I don't want to get into a whole "thing" here, but just to give an example, regarding his divided metol-sulfite formula (which is essentially Dalzell's modification of Stoeckler's), Thornton's comments about the alkali in bath B are flawed. To be fair, it isn't just Thornton. In general the descriptions and directions for divided development (where bath A is a developer), are somewhat flawed.

    All I'm saying is be careful when you read technical books written by photographers, particularly when it comes to chemistry and sensitometry. The science is often incorrect and no evidence is presented. And when someone claims to be tweaking a scientifically balanced commercial formula such as Perceptol, have a healthy scepticism.

    There's a lot of bad information out there - in books too.

    Then again, if Thornton's formulas give you results you like, that's all that matters. My point here was not to worry too much about a Thornton version of Perceptol. That type of developer has been done, redone, and re-redone by Kodak and Ilford already.

  6. #6
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    I am not trying to put anyone on the spot here. I have heard this type of statement before and am only curious.

    I have mixed & used a few of the formulas printed in some of the books I have read, including Edge of Darkness, and they did work for me. I am not quite so persnickety as Mr. Thornton or others, so I don't use these formulas regularly and I can't even say that I love them or not. Personally I find that simple D76 or Rodinal do what I need most of the time but once in awhile I like to experiment. Most of the time I experiment, not because I intend to change how I do things entirely, but because it helps me understand more about what I am doing.

    Thanks for the explanation. It sounds more like a precaution to try things out a bit before you accept them as gospel.
    Dan

    The simplest tools can be the hardest to master.

  7. #7
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    Quote Originally Posted by Michael R 1974 View Post
    I don't want to get into a whole "thing" here, but just to give an example, regarding his divided metol-sulfite formula (which is essentially Dalzell's modification of Stoeckler's), Thornton's comments about the alkali in bath B are flawed. To be fair, it isn't just Thornton. In general the descriptions and directions for divided development (where bath A is a developer), are somewhat flawed.

    All I'm saying is be careful when you read technical books written by photographers, particularly when it comes to chemistry and sensitometry. The science is often incorrect and no evidence is presented. And when someone claims to be tweaking a scientifically balanced commercial formula such as Perceptol, have a healthy scepticism.

    There's a lot of bad information out there - in books too.

    Then again, if Thornton's formulas give you results you like, that's all that matters. My point here was not to worry too much about a Thornton version of Perceptol. That type of developer has been done, redone, and re-redone by Kodak and Ilford already.
    +1

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

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    Quote Originally Posted by Michael R 1974 View Post
    be careful when you read technical books written by photographers, particularly when it comes to chemistry and sensitometry. The science is often incorrect and no evidence is presented. And when someone claims to be tweaking a scientifically balanced commercial formula such as Perceptol, have a healthy scepticism.

    There's a lot of bad information out there - in books too.
    All too true. I would also add that there is no magical developer, no "holy grail" of developers. People spend too much time in this fruitless search. Ansel Adams specifically warns against this in his preface to The Negative.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #9

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    I have "Edge of Darkness" and cannot find any reference to his "version of Perceptol".
    All he says, p102, is "I am at time of writing working on getting even higher definition from this Perceptol type."
    I am not aware that he ever claimed to have succeeded.

  10. #10

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    Quote Originally Posted by Alan Johnson View Post
    I have "Edge of Darkness" and cannot find any reference to his "version of Perceptol".
    All he says, p102, is "I am at time of writing working on getting even higher definition from this Perceptol type."
    I am not aware that he ever claimed to have succeeded.
    That all I was wondering. He talks about working on it, but that's all I could find out. It really doesn't matter since I have some Perceptol stocked up and really have been stuck on Pyrocat-MC for most of my films now anyway. Just souped some HP5+ 120 in Pyrocat-MC last night and scratched my head as to why I would mess with anything else. Very nice results that's for sure, but I still like the look I get with PanF+ and Perceptol. JW

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