Page 2 of 22 FirstFirst 123412 ... LastLast
Results 11 to 20 of 212

Thread: pyro developer, but which?

  1. #11

    Join Date
    Sep 2003
    Location
    Seattle, Washington
    Posts
    3,022

    Re: pyro developer, but which?

    Hi Ken,

    You're correct; the formula as given makes 100ml of concentrate, and I call it 510-Pyro for the ratio of pyro to ascorbic acid.

    510-Pyro can be diluted over a very wide range, but "standard" dilutions could be considered to be 1:100, 1:300, and 1:500, for no better reason than the following: 1:100 gives development times within the low-normal range (5-7 minutes for most films), with standard intermittent, or rotary agitation, 1:300 requires 1ml of developer in 300ml of solution, which covers one 35mm film in a standard daylight tank, and 1:500 requires 1ml of concentrate in 500ml of solution, which covers one 120 film in a standard daylight tank. These dilute solutions are typically used with reduced agitation and extended development times. There is more specific information at the blog.

    I make the distinction between pyrogallol developers and catechol developers consistent with historical usage. When pyro is mentioned in the literature, it always refers to pyrogallol, and not to catechol, and the descriptions and characterizations of pyro are not interchangeable with catechol. Catechol is chemically more similar to hydroquinone than it is to pyrogallol, and this can be confirmed by the fact that catechol can be substituted for hydroquinone weight-for-weight in most formulas without important changes in the resulting developers. The same is not true for pyrogallol and catechol. In my opinion, which is consistent with the historical literature, catechol developers should not be referred to as pyro developers, but staining/tanning developers, where appropriate (not all catechol developers are staining developers). I hope that clarifies my usage of the terms.

    If you decide to try 510-Pyro, or any of my developers, please don't hesitate to contact me with any questions you might have.

  2. #12

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,171

    Re: pyro developer, but which?

    I personally believe it is a waste of time equivalent to intellectual masturbation to attempt to limit the use of the term pyro staining developer to only pyrogallol based formulas. The word pyro itself has wide meanings both in photography and in general use and does not refer to any specific reducing characteristic of either pyrogallol or catechol (which was historically better known as either pyrocatechol and pyrocatechin).

    As for which is the best pyro formula, I am reminded of something that was recently said to me in my travels in Galicia, in northwestern Spain. I was photographing there for a couple of weeks with a well-known landscape photographer from the area who has published a number of books, who actually uses a very old pyro-metol formula that pre-dates any of the modern formulas. He mentioned that he recently took someone to buy some “corn cakes” (tortas de maiz) from a person who is widely known for making the best cakes of this kind. The person asked, “Do you make the best corn cakes in Galicia?” to which the baker replied, “Eso tem que decir a torta, non eu” Translated, the cake has to speak to that, not me. So by analogy, I say, let your pictures talk.

    Sandy King
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at Yahoo.
    https://groups.yahoo.com/neo/groups/...nTransfer/info

  3. #13

    Join Date
    Sep 2003
    Location
    Massachusetts USA
    Posts
    7,833

    Re: pyro developer, but which?

    I confess, I'm confused.

    Apparently, Catechin is derived from certain plants, and if you heat it (pyro) you can break off a molecule of Catechol (hence the name pyrocatechol).

    In the image below, you can see a Catechol molecule, loosely bonded to a (larger) Catechin molecule.

    According to Catechin in Wikipedia...

    "Catechin... derives from catechu which is the juice or boiled extract of Mimosa catechu"



    According to Catechol in Wikipedia...

    "Catechol, also known as pyrocatechol... Not to be confused with Catechin, also sometimes called catechol."

    Last edited by Ken Lee; 5-May-2010 at 10:09.

  4. #14

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,171

    Re: pyro developer, but which?

    Quote Originally Posted by Ken Lee View Post
    I confess, I'm confused.

    Apparently, Catechin is derived from certain plants, and if you heat it (pyro) you can break off a molecule of Catechol (hence the name pyrocatechol).
    %29-Catechin.png/200px-%28%2B%29-Catechin.png[/IMG]
    Hydroquinone (1,4,-Dihydroxybenzene), Catechol/Pyrocatechol (1,2-Dihydroxybenzene) and Pyrogallol (1,2,3-Trihydroxybenzene) are quite similar and while each can produce a stain in favorable circumstances (absence of preservative) neither is fully interchangeable with the other two. Hydroquinone can be substituted for pyrocatechol but does not give the same result (different color stain and different energy if substitution is by equal weight), and pyrocatechol can be substititued for pyrogallol in formulas that use carbonate as the accelerator (but equal weight substitution will not give identical results. Hydroquinoine and pyrocatechol can not be substitued for pyrogallol in formulas that use metaboate as the accelerator.

    Sandy King
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at Yahoo.
    https://groups.yahoo.com/neo/groups/...nTransfer/info

  5. #15

    Join Date
    Sep 2003
    Location
    Massachusetts USA
    Posts
    7,833

    Re: pyro developer, but which?

    Another question if I may, namely the difference between staining and tanning - and for that matter, dyeing.

    With a stain or dye, we introduce a new compound deep into the matrix of the original material. With tanning, we coat the surface of the material, but do not penetrate very far below the surface.

    By this analogy, a stain would be like a coloring stain we commonly apply to wood products, where tanning would be more like paint, applied to the surface.

    If this is true, then as far as photography is concerned, what is the qualitative difference between developers which stain, and those which tan ?

  6. #16

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,171

    Re: pyro developer, but which?

    Quote Originally Posted by Ken Lee View Post
    Another question if I may, namely the difference between staining and tanning - and for that matter, dyeing.

    With a stain or dye, we introduce a new compound deep into the matrix of the original material. With tanning, we coat the surface of the material, but do not penetrate very far below the surface.

    By this analogy, a stain would be like a coloring stain we commonly apply to wood products, where tanning would be more like paint, applied to the surface.

    If this is true, then as far as photography is concerned, what is the qualitative difference between developers which stain, and those which tan ?
    Ken,

    Stain adds printing contrast with graded silver papers and UV processes. It also can create a shoulder in the highlights with VC silver papers that can control very high tonal values. Stain also minimizes the appearance of grain. With enough preservative (sulfite, ascorbic acid, etc.) both pyrocatechol and pyrogallol based developers will lose the stain, but grain will be much more pronounced.

    Tanning adds sharpness as it hardens the gelatin in situ and prevents infectious development outside of the desired image area. However, staining and tanning do not always go together as you can have staining without tanning, and vice-versa. Most modern pyro developers do both, however.

    Sandy King
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at Yahoo.
    https://groups.yahoo.com/neo/groups/...nTransfer/info

  7. #17

    Join Date
    Sep 2003
    Location
    Seattle, Washington
    Posts
    3,022

    Re: pyro developer, but which?

    Sandy,

    Masturbation aside, I know of no instance in the literature I've read, and I don't mean to suggest I've read everything, in which the term pyro is used to refer to anything but pyrogallol. I see no reason to confuse this very old convention by the inclusion of other compounds. I use the term, staining developer to refer to all developers that produce a useful stain. Pyro belongs to this class of developers, when used in appropriate formulations, as do catechol, hydroquinone, coffee and tea developers. When one reads historical literature and comes upon the the term pyro, one can be confident the authors are referring to pyrogallol; why confuse the issue? I use catechol, as opposed to pyrocatechol, or pyrocatechin, or catechin, because that's how the chemical is listed by most suppliers, and I don't feel there's much danger of the term being confused for something else. Maybe I'm overly cautious in my use of language, but with so much confusion surrounding these developers, I feel justified in my efforts to be as clear as I can in my writing and in the terminology I use. For instance, consider the description of Pyrocat HD, from the Photographers Formulary website:

    Pyrocat HD is a high acutance developer, formulated by Sandy King as an alternative to other pyrogallol based staining developers.
    The use of the word other, implies Pyrocat HD is a pyrogallol-based developer, and since pyro is used in the product name, it's a logical assumption to make, if one is not intimately familiar with the compounds and formulations in question.

    Others are free to use any terminology they prefer; I just meant to explain why I use the terminology I do, and not to suggest anyone is wrong for using alternative terms.

    As for your corn cake analogy, you sum up as "Let your pictures talk", I feel that is a little aggressive in addition to being a gross oversimplification, unless of course, you believe developer choice is the one factor that determines the quality of an image. Personally, I feel developer choice borders on irrelevance, regarding image quality, for most LF photographers.

    Ken,

    Here's a link to a brief description of tanning and staining:

    http://pyrostains.blogspot.com/2007/...d-tanning.html

    In a nutshell; staining colors, and tanning hardens. The fact that tan, can be used to refer to a color, or a change of color, as in: tan trousers, or suntan, can be confusing, but the tan in tanning developers, is derived from the word tannin:

    http://en.wikipedia.org/wiki/Tannin

    I hope I've clarified rather than confused.

  8. #18

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,171

    Re: pyro developer, but which?

    Jay

    You are perfectly free to use any terminology you like. It is true that in the 19th century pyro meant pyrogallo. Indeed, pyrocatechol was not even invented until around 1880. However, in the contemporary period a number of pyrocatechol based staining developers, in addition to Pyrocat-HD, have been routinely referred to as pyro developers. These include Diaxactol, which preceded Pyrocat-HD, as well as Prescysol and Tanol. But more important than practice is the fact that pyrogallol based and pyrocatechol based developers do essentially the same thing in the way they stain and tan. In fact, the differences between them are more apt to be in the other reducer used in the formula, in the method of agitation, or in the choice of accelerator.

    So my own opinion is that it is simply not consistent with current practice, or common sense, to limit the use of pyro to pyrogallol based developers, but then again you are free to use any terminology you like, and ultimately what you or I think is probably not going to make much difference as to what others choose to do. And that is why I think the discussion is essentially pointless.

    As for my corn cake analogy being in your opinion a bit aggressive, it was not meant that way and I see no reason why you would take it that way since the comment was generally directed, not toward you. The original question was "which pyro developer"? and if the ability to produce image quality is irrelevant to that question it is not clear to me why we would be talking about developers in the first place.

    Sandy
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at Yahoo.
    https://groups.yahoo.com/neo/groups/...nTransfer/info

  9. #19

    Join Date
    Sep 2003
    Location
    Seattle, Washington
    Posts
    3,022

    Re: pyro developer, but which?

    Sandy,

    You might be right about some catechol developers being referred to as pyro developers; I've just not seen these references in my reading, which has consisted mostly of 20th century literature, and as recent as I could find. In fact, in Barry Thornton's Edge of Darkness, Thornton distinguished between pyro developers and catechol developers, the former being developers based on pyrogallol. Jacobson and Jacobson in Developing similarly don't interchange the two, but refer only to pyrogallol-based developers as pyro developers, and so on with everything I've read . I'm not sure where catechol developers are referred to as pyro developers, but I'll take your word for it. Is it an important distinction to make? I think so. Pyrogallol developers have a separate history from catechol developers, and I find it more accurate to refer to pyrogallol developers as pyro developers, and catechol developers as catechol developers, and to all staining developers as staining developers. When one reads about the working methods of revered photographers, like Weston, or Adams, and their pyro developers, there is no need to wonder whether they used pyrogallol or catechol, because pyro is historically specific to pyrogallol developers. This is more clear to me, and a more common sense approach, than lumping all staining developers together as pyro developers. But, to each his own.

    I'm sorry if I misinterpreted your corn cakes analogy as suggesting superior developers make superior images. I'm not sure what else, "let your pictures do the talking" could mean. In any case, it's not very useful in the context of a discussion about the relative merits of various staining developers. Weston made some pretty nice pictures with ABC Pyro, but that shouldn't suggest that developer was responsible, or that he couldn't have made his pictures as well, or better with another developer. "Let your pictures do the talking" is a meaningless statement in this context.

    As for my statement, I wrote: ..developer choice borders on irrelevance, regarding image quality, for most LF photographers. , and I stand by that. But, the OP's question wasn't, "How important is choice of developer for LF photographers?", it was, "Which pyro developer is best?". The latter is a specific question about pyro developers, on which I feel qualified to comment. While I made a distinction between pyro and catechol developers in my post, I did include information about both kinds of staining developers, because I suspect many photographers, particularly those unfamiliar with them, think only of pyrogallol developers when they refer to pyro developers, and might not be aware there is more than one kind of staining developer, and they're not all pyrogallol-based.

    In the end, whether one refers to all staining developers as pyro developers, or just pyrogallol developers, is of little importance, so long as it's understood who refers to which as what.

  10. #20

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,171

    Re: pyro developer, but which?

    Quote Originally Posted by Jay DeFehr View Post

    I'm sorry if I misinterpreted your corn cakes analogy as suggesting superior developers make superior images. I'm not sure what else, "let your pictures do the talking" could mean. In any case, it's not very useful in the context of a discussion about the relative merits of various staining developers. Weston made some pretty nice pictures with ABC Pyro, but that shouldn't suggest that developer was responsible, or that he couldn't have made his pictures as well, or better with another developer. "Let your pictures do the talking" is a meaningless statement in this context.
    You rather misunderstood my meaning. My comment about the pictures talking was not meant to suggest there was a superior developer, but in fact to downplay the importance of any given formula, the very opposite of your interpretation.

    Photographers who have a vision make superior photographs because they understand their tools, of which the developer is one of many. Weston made great photographs because of his great talent and because he knew how to control his tools, including ABC Pyro. I am certain that he could have learned to control other developers as well, but the fact is that he used ABC Pyro almost exclusively for much of his career because he understood how it worked and knew how to take advantage of its characteristics.

    Developers, whether pyro or traditional, are not inherently either good, bad or in between. Same is true of films. They have characteristics which one must learn how to control. When one learns this control, the pictures do the talking. One may compare the various characteristics of different developers and films but that will tell you little or nothing about what kind of images a given photographer will produce when using any given combination.

    Sandy King
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at Yahoo.
    https://groups.yahoo.com/neo/groups/...nTransfer/info

Similar Threads

  1. Bostick & Sullivan Pyro PMK developer - HELP
    By htswv in forum Darkroom: Film, Processing & Printing
    Replies: 7
    Last Post: 2-May-2010, 10:37
  2. Question concerning usage of Pyro developer
    By Kaden Kratzer in forum Darkroom: Film, Processing & Printing
    Replies: 6
    Last Post: 27-Apr-2009, 09:13
  3. Old Formulas : Film
    By Paul Fitzgerald in forum Darkroom: Film, Processing & Printing
    Replies: 6
    Last Post: 19-Mar-2005, 21:31
  4. Pyro Developer
    By Kent McClelland in forum Darkroom: Film, Processing & Printing
    Replies: 2
    Last Post: 12-May-1998, 20:13

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •