PMK or Divided D76greenspun.com : LUSENET : Large format photography : One Thread
Do those with experience using PMK and divided D76 have a preference for one over the other in terms of its ability to produce a good long scale negative with adequate highlight separation?
I ask as I am considering D76 as an occasional alternative to PMK.
-- Paul Giblin (email@example.com), January 04, 2002
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.
-- Pete Caluori (firstname.lastname@example.org), January 04, 2002.
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.
-- Scott Walton (email@example.com), January 04, 2002.
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.
-- Dave Karp (firstname.lastname@example.org), January 04, 2002.
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.
-- Ted Kaufman (email@example.com), January 04, 2002.
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 (firstname.lastname@example.org), January 04, 2002.
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?
-- Ted Kaufman (email@example.com), January 05, 2002.
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 (firstname.lastname@example.org), January 05, 2002.
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.
-- N Dhananjay (email@example.com), January 05, 2002.
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.
-- Ted Kaufman (firstname.lastname@example.org), January 05, 2002.
DJ - When you say you see a difference, do you mean you've made a series of identically exposed negatives, developed one set in PMK for the "correct" PMK time for the contrast range of the scenes in that series of negatives as determined from proper testing, and the other set in a "normal" developer for the "correct" time for that developer as determined from proper testing, made the best print you can make of the PMK negative, and then were unable to duplicate that print from the "normal" negative? (i.e. your PMK prints were visibly different in some way from your "normal" prints despite your best efforts to make them appear identical). If that's what you're saying I'd like very much to see several of the comparison prints you used. If you're agreeable let me know by e mail and I'll send you an envelope with the postage prepaid so that you can send the prints to me and I'll return them to you in a couple days. I don't mean this sarcastically or as a snide "I dare you" challenge, I'm seriously interested in seeing your results because three people, two of us reasonably knowledgeable photographers and the third a photography teacher, tried to do this and we were unable to do it (i.e. we could always make a print from the "normal" negative that duplicated the print from the PMK negative). OTOH, if this isn't what you've done, and if instead you're just looking at some negatives developed in PMK and concluding that they look "sharper" or "better" than some entirely different negatives developed in other developers, then I don't think your observations are very significant or valid. Even assuming you can draw valid conclusions about two developers by looking at a random bunch of entirely different negatives (which I don't think you can do), if the differences in the negatives don't translate into differences in the prints, then who cares what the negatives look like?
-- Brian Ellis (email@example.com), January 06, 2002.
There is an interesting article on www.unblinkingeye.com called the effects of Pyro Stain. While this article is concerned with the results of pyro VS D-76 for platinum contact printing it might provide some insight for those interested.
-- James Christian (firstname.lastname@example.org), January 06, 2002.
I should preface this by saying that I don't consider my testing very exhaustive or anything of the kind. I was more interested in finding something that worked for me and getting on with making pictures. What I stated above was my understanding based upon both the test I did, and in looking at a large number of negatives that I have shot and developed in the different developers. Details about test below. However, as much as I like data based upon tests, I think the second part (my subjective opinion based upon comparing different, non-test negatives) is important also because we shoot varied scenes. And the kind of scene doesplay a part in determining whether a particular variable (type of developer) makes a significant difference or not. And it is something that would be too onerous to test, so I fall back on my comparisons of negs.
First, the test. Yes, I exposed a few scenes and developed them in a Catechol developer and D23. The basic idea was to develop them to the same contrast - I used the methodology Phil Davies outlines in his book. What I find is that for 'normal' scenes (i.e., a scene consisting of about 5 stops for luminance differences - typical zone III to zone VII kind) and a decent amount of texture, I could not see any differences between the two developers (both in the negative and in the print) - there were some differences, very subtle stuff that could be as much due to minor differences in curve shape etc (see below) but nothing dramatic. Depending upon the kind of scene etc., you may find a difference in that one developer may exhibit enhanced acutance or adjacency effects etc., although this is going to depend upon the scene and how much detail there is and so on. However, when it comes to other kinds of lighting situations (e.g., a long range of luminance values, a contraction negative, low local contrast in the highlights), the staining developer held texture in the highlights more easily.
Caveats: There were some other differences between the two developers. Most importantly, I'm afraid given my processing conditions, I could not get idential curve shapes, the D23 did have a shoulder compared to the Catechol developer.
Two negatives (not part of my test) that reveal this most clearly (to me) are pictures of ice on a lake with the glare of the sun on the ice in one area. The D23 negative is 'blocked', if I expose the negative enough to print through, I get a textureless 'grey' - I interpret this as meaning that irradiation within the emulsion has reduced local contrast in this area considerably. However, the Catechol developed negative prints with texture - I interpret that to be due to the tanning that prevents irradiation.
I did not mean to imply that your tests were wrong. I was merely adding another data point to the discussion. It is entirely possible that there is something idiosyncratic such as 'kind of scene' that determines whether one will see differences between developers etc. And I think the point you make is a valid one. If the kind of pictures one wants to make does not benefit from staining developers, there is little to be gained by going to PMK or anything like that. Hutchings himself states that pyro's advantages tend to reveal themselves in 'difficult light' - I interpret that as meaning that certain kinds of light and certain kinds of scenes will be handled more easily in pyro (and I'm sure there are other kinds of scenes that are more easily handled by other kinds of developers).
-- N Dhananjay (email@example.com), January 07, 2002.
I did fairly extensive testing last Summer, using 120 film (Ilford Delta 100 and 400) developed either in XTOL 1:1 or PMK. (I took 2 exposures of each scene, one for XTOL the other for PMK processing, so it was a true side-by-side test). My first impression was, "wow, these PMK negatives are truly spectacular", which is where some of the PMK-mystique may stem from. When making carefully contrast- balanced prints, most of the mystique disappeared. I am not saying there was no discernable difference anymore between the prints (which would be surprising, since the densitity curves of film/developer combinations will never be the same) but I had a hard time to say which one was "more beautiful". Sometimes the edge went to the PMK, sometimes to the XTOL print. When making HUGE enlargments (20x24 from 120 negs) then the PMK negs always had better acutance. These are some of the sharpest negs I ever got. They are as good as TMX in Rodinal 1:50, but without the grain! For LF photographers who don't need to enlarge quite as much, this may not be important. In MF, I am sticking with PMK though. The largest drawback to me is not the toxicity (no problem if one works carefully) but the loss of film speed (a little more than 1 f-stop).
-- Andreas Carl (firstname.lastname@example.org), January 12, 2002.
Anyone tried a kind of "divided PMK" ? This is not a joke or for the sake to try something original. I have been using PMK since 1996 and I found it gives superior results than non taning developers in situations of high brightness range ; otherwise, the results are close, but it is easier to stick with one developer you know well. I am a PMK enthousiast ! A good test I made once : take a picture of a nautilus cut in half (like the one taken by Weston) ; the glaring surface and the sharp edges of the shell will be shown with micro details and a subtlety in highlights that is better recorded. In MF and LF, grain is not a problem with PMK. In 35 mm, grain matters : you need a beautiful grain wether it is discret or clearly visible. If you use films not faster than 100/125 ISO, grain is not a problem with PMK. But for 400 ISO in 35 mm I find the shape of the grain in the shadows too similar to what you get from an underexposed color negative film : disturbing. Well, a D76 grain is more beautiful in this part. I like TMY for 35 mm ; I won't say it is the best film : I like it. I tested all 400 ISO, and found I prefer this one in 35 mm because of the resolution, size and shape of the grain. Once the contrast of TMY is controled, I find it a good film. TMY has the same problem of grain in the shadows than any other 400 ISO film in PMK. I like to take pictures with "contre-jour" or high brightness range ; and PMK does a good job in highlights. I wondered if Divided D76 could give me the grain of D76 with the highlights of PMK. I tried but the grain was there but not the same quality of PMK highlights. TMY can record a lot of information in highlights, but divided D76, while keeping highlights with details, those details were flater than what I get with PMK. To get advantages of both developer, I tried a divided... PMK. For the first bath, I use 5 g of metol with 50 g of sulfite. For the second bath, PMK. 4 mn in bath A (70°F/21°C) and 4 mn in PMK. No rinse between the two baths, like any two baths development. I use an alkaline bath after fix (as in the PMK procedure). The negatives have a stain, but not as much as with a normal PMK development. The result ? I get the grain I like in the shadows and the highlights print with all the details I am looking for. Contrast can be controled with varying times in A and B or with temperature : low contrast : 3+3, high contrast : 5+5. It would be interesting to have your opinion on that subject. And be lenient with my English...
-- Philippe Bachelier (email@example.com), January 27, 2002.