Page 1 of 2 12 LastLast
Results 1 to 10 of 15

Thread: PMK or Divided D76

  1. #1

    Join Date
    Jul 2001
    Location
    Massachusetts
    Posts
    17

    PMK or Divided D76

    Do those with experience using PMK and divided D76 have a preference for one ove r the other in terms of its ability to produce a good long scale negative with a dequate highlight separation?

    I ask as I am considering D76 as an occasional alternative to PMK.

    Thanks, Paul

  2. #2

    PMK or Divided D76

    Greetings,

    I've not used PMK, but instead use ABC+ Pyro; the formulation varies only slightly. IMHO if your desire is a long scale neg, with highlights that do not block, then Pyro is the way to go. Divided D76 is a good developer and certainly easier to use than Pyro, but I have seen instances where highlights became too dense. Granted it doesn't usually happen, but it can. Pyro OTOH is more tollerant in that regard.

    Regards,

  3. #3

    PMK or Divided D76

    I have used DD76 extensively as well as Diafine and love them. The tonal range is superb and the added acutance of Diafine is beautiful. They both are extremely fine grain and really don't overdevelop due to their compensation. I haven't done the PMK so I really cannot give my opinion on that or any Pyro developers.

  4. #4
    Dave Karp
    Join Date
    Dec 2001
    Location
    Los Angeles, CA
    Posts
    2,824

    PMK or Divided D76

    Scott,

    I am just getting ready to test Diafine after not using it for many, many years. (My Dad taught me how to develop film with it when I was a child.) What film(s) do you use, and what EI do you use? Sheet or roll film? Do you adjust the EI to alter contrast? What type of photography do you do?

    Thanks in advance.

  5. #5

    Join Date
    Jul 2001
    Posts
    76

    PMK or Divided D76

    I've never tried divided D-76, but I can offer that PMK is made to order for the needs you've described. Developers based on pyro (PMK) and catechol are particularly suited to long scale subjects that require defined highlight separation.

  6. #6

    Join Date
    Dec 1997
    Location
    Baraboo, Wisconsin
    Posts
    7,695

    PMK or Divided D76

    I've tested PMK extensively and compared it with identical negatives developed in D 76 (not divided D 76). There was no visible difference between prints made from PMK negatives and prints made from negatives developed in D 76. Others have made the same comparison tests using HC 110 with the same result. Despite the aura surrounding it, the objective testing I've done and seen done by others doesn't support the idea that PMK negatives result in prints that are visibly different in any way from prints made with negatives developed normally. So my suggestion would be to ignore PMK given its trouble, expense, and toxicity, and just use divided D 76. My only qualification to this is that when the testing was done (last summer) we were following Gordon Hutchings' recomendation to rinse the negatives in used PMK for two minutes after fixing and before washing. Since that time I've heard three different knowledgeable people say that this step should be omitted because it just adds overall density rather than proportional density. I haven't yet done any testing with that step omitted. If anyone has, I'd like to hear from them.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  7. #7

    Join Date
    Jul 2001
    Posts
    76

    PMK or Divided D76

    Brian: I don't know how controlled your test conditions were in which you compared the relative merits of D-76 and PMK, but from reading your post one might conclude there is no difference in the tonality, scale, sharpness and grain between a print from a D-76 negative and another from a PMK negative. And by extention from your comments, there is also no difference between HC110 and PMK, thus no difference between HC110 and D-76. From your post, one would conclude there is no diffence in developers at. You're joking, right?

  8. #8

    Join Date
    Dec 1997
    Location
    Baraboo, Wisconsin
    Posts
    7,695

    PMK or Divided D76

    I guess I wasn't clear so I'll try again. My test procedure consisted of first determining developing times for PMK (I already had those times for D 76 since that's what I've been using for years). After doing that, my testing procedure consisted of making a series of two identical negatives of various subjects, developing one set in PMK and one set in D 76, then making prints from each set of negatives. I could always make a print from the D 76 negatives that was visually identical to the print made from the PMK negative. In other words, PMK wasn't imparting any special qualities to the prints that I or anyone to whom I showed the prints could see. Two friends of mine were doing the same thing at the same time, more or less independently of me. One of them was using HC 110 instead of the D 76 that I was using. He too could match prints made from his HC 110 negatives to prints made from his PMK negatives. I wasn't saying that all developers are identical, only that the results obtained from PMK seemingly can be obtained with at least two other developers (D 76 and HC 110). Hopefully that's clear. If not, let me know and I'll try again.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  9. #9

    Join Date
    Mar 1999
    Posts
    769

    PMK or Divided D76

    I'm afraid I DO see a lot of differences between negs developed in D76/D23 type developers and staining developers. And I would come down on the side of the staining developers for long scale subjects. The main reason has little to do with the stain and more to do with the tanning action of pyro and catechol. The tanning action means that these are surface-acting developers.

    The biggest problem I have encountered with conventional developers of the D76 type is the fact that the develop in the depths of the emulsion as well as the surface - this means that irradiation is a huge problem. Keep in mind that irradiation is a bigger and bigger problem in the more heavily exposed areas (even in the so-called thin emulsion films). Thus, acutance is severely curtailed in the heavily exposed areas. Most people complain about 'blocking'. This 'blocking' is not due to the highlights ending up on the shoulder of the curve (modern films go on for a long time before hitting a shoulder). The 'blocking' is really due to irradiation within the emulsion which reduces acutance and results in highlights with no textural content at all. Keep in mind that this is further exacerbated by the solvent action in the D76 type of developer - silver (on the surface and in the depths of the emulsion) is etched away by the sulfite and replated back. Hutchings says that microscopic analysis shows a silver speck and a large diffuse area (presumably the replated part).

    Staining developers tan the gelatin and as a result are surface developers. This should be quite apparent - a negative developed in pyro or catechol looks unreally sharp, due both to the fact that there are enhanced adjacency effects, and the fact that the surface acting nature means that there is little loss of acutance to irradiation. More importantly, the fact that there is no irradiation means that the highlights maintain texture - the acutance that is essential for providing detail and texture in areas is not destroyed by irradiation in the emulsion.

    Given the toxic nature of some of these chemicals, it would be great if the results were achievable in some other fashion. But I'm afraid I haven't seen that. Compensating development of any kind (water bath, divided development, dilution, reduced agitation) basically puts a shoulder on the film curve. While it may allow highlights to be printed, the highlights will have reduced local contrast due to the lower slope in the shoulder that has been put on the film curve. Staining developers don't put a shoulder on the curve but provide enhanced acutance, even in the highlights. In other words, the gradation genuinely seems better.

    Cheers, DJ.

  10. #10

    Join Date
    Jul 2001
    Posts
    76

    PMK or Divided D76

    DJ: That was a remarkably cogent analysis. Moreover, my own experience using PMK and catechol developers supports your findings precisely.

    High SS content developers like D-76 and D-23 consistently yield bright, bald highlights compared to negatives developed in tanning developers. But there is more: I've never seen any variation of D-76 or D-23 achieve the richness or smoothness of midrange values characteristic of PMK and catechol developers. That is not to say D- 76 will not produce good images, but it surely does not look like PMK, et al. Also, edge acutance and micro detail are crisper and obviously superior with tanning developers, and this, due to the masking effect of stain (which clearly contributes to the illusion of tonal smoothness), is achieved without the apparent graininess typical of high acutance developers--especially in skys and other highlight areas because they don't require extensive burning to hold texural detail.

    Brian, if you've never seen these differences, I'm sorry.

Similar Threads

  1. Questions concerning stoeckler divided developer
    By Robert Haury in forum Darkroom: Film, Processing & Printing
    Replies: 3
    Last Post: 19-Sep-2001, 06:12
  2. Divided D23, The Perfect Film Developer?
    By Jeff_1630 in forum Darkroom: Film, Processing & Printing
    Replies: 3
    Last Post: 9-Apr-2001, 09:46

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
  •