Originally Posted by steve simmons
When I first saw this message a few days ago I started to respond but did not have the time to give the issue the attention it deserves. First, let me state that Steve’s personal satisfaction with PMK based on 25 years of experience is not surprising. PMK is without question one of the best all around developing formulas available and I used it for almost ten years as my primary developer. But let me begin with two preliminary observations.
1. I know a photographer who has used D-23 for more than twenty-five years and would not consider changing to another developer. The fact that we are satisfied with our developer and don’t feel a need to change is ample reason to not do so, but it does not mean that a given developer is better than another.
2. Steve’s statement that in his opinion the best of the formulae is still the PMK developed by Gordon Hutchings in the early 1980s suggests that he has actually compared the current crop of Pyro formulas. At least that is how I understand the issue because I personally would not say that one developer was better than another unless I had some experience with both of them. So, Steve, if you have actually made any objective comparisions of PMK with other Pyro developers please show your criteria, methodology and results.
It is my understanding that Steve plans to publish an article in View Camera at some time in the future comparing pyrogallol and pyrocatechin developers, perhaps directly comparing PMK and Pyrocat-HD. Let me state right here that since I have used and tested both of these developers extensively I already know what a well-designed comparison test of the PMK and Pyrocat-HD will find. And I am going to reveal some of that information here now. My criteria for comparison are, 1) sharpness and grain, 2) rendition of tonal values, and 3) versatility, and 4) suitability as dual-purpose negatives to print with both silver and Pt/Pd. Some of these criteria may not be important to many readers but they are all important in evaluating the two developers in terms of their overall versatility.
1. Sharpness and Grain.
First, let’s start with the points of similarities between PMK and Pyrocat-HD. Both are semi-compensating high definition developers staining developers . When used at the recommended dilutions for silver printing (1:1:100 for Pyrocat-HD, 1:2:100 for PMK) they give negatives that are virtually identical in terms of sharpness and grain.
I tested sharpness and grain in two way. First, I made two identical exposures of an outdoor scene with a 4X5 camera, and after calculating time of development needed for an equivalent CI, developed one in PMK and another in Pyrocat-HD. Then I made 20X24” prints from the negatives.
Result: At 5X magnification there was no discernible difference in either sharpness or grain between the two prints.
So I tested again for higher magnification, using a Fuji 6X9 cm camera with a 90mm Fujinon EBC lens, obviously on a tripod. I made eight exposures on Tmax 100 120 roll film of the Edmund Scientific Company Resolving Power Chart, a reproduction of the USAF 1951 Test Pattern. I made exposures at f/5.6, f/8, f/11 and f/16, then repeated the sequence. In the darkroom I cut the 120 film into two equal lengths and developed one set in PMK and the other in Pyrocat-HD. I dried the negatives and them examined them at 40X magnification with a Bausch and Lomb stereoscopic microscope.
Result: The resolving power of the 90mm Fujinon EBC lens approached 100 lpm with both PMK and Pyrocat-HD negatives. Clearly the limitation to resolving power was in the optical system and/or film, not in developers.
Ditto for grain. Virtually no difference between the two negatives.
Conclusion. At a magnification size of 40X (that would equate to a print size of 90”X 90” from a 6X6 cm negative) there is for all practical purposes no difference in sharpness or grain between PMK and Pyrocat-HD negatives.
Do we need to say anything more about sharpness and grain?
2) Rendition of tonal values.
When developed to the same CI, PMK and Pyrocat-HD give negatives that print the same on graded silver papers, which are sensitive to blue light. With VC papers there are issues. For a complete explanation of these issues see my article on staining developers at http://unblinkingeye.com/Articles/PCat/pcat.html. But the bottom line is that PMK has more of an effective shoulder than Pyrocat-HD, the practical result of which is that in scenes of great contrast range PMK holds highlight detail better than Pyrocat-HD. But, with developers you don’t get something for nothing, and the down side of the shoulder is that with VC papers PMK negatives print the upper mid-tones and highlights with less separation (= less contrast) than Pyrocat-HD negatives. If you don't believe me on this just check the literature because there have been many comments by PMK users about lack of separation or contrast in upper mid-tone separation in certain kinds of lighting.
Conclusion: The differences in shoulder are developer characteristics, not advantages or disadvantages. When printing with VC papers some scenes would print better with PMK while others would work better with Pyrocat-HD.
Based on my research and experience there is little question but that Pyrocat-HD is a more versatile developer than PMK. The main reason is that pyrocatechin is more stable in alkaline solutions than pyrogallol and it oxides much less rapidly. The practical consequence of this fact is that Pyrocat-HD works equally well in both tank, tray and rotary (Jobo, BTZS tubes) processing, and with all kinds of agitation, including minimal and semi-stand. This means that you can use Pyrocat-HD with minimal and semi-stand agitation to maximize adjacency effects and apparent sharpness. With PMK you can not use these types of agitation because the rapid oxidation of the developer requires frequent agitation to avoid uneven staining.
4) Suitability as dual purpose negative for silver printing and printing with Pt/Pd.
Again, see my article for a fuller explanation of why Pyrocat-HD negatives are more suitable than PMK negatives as dual purpose negatives for printing with both silver and Pt/Pd (and other alternative processes sensitive to UV radiation). This is due to the fact that Pyrocat-HD negatives have a much greater difference between the effective printing density for UV light processes and blue sensitive light processes than PMK. This results from the fact that a much higher percentage of the effective printing density of a Pyrocat-HD negative consists of brown stain, which functions as a much more effective filter to UV light than the green stain of PMK negatives.”
Consider for example the following density reading of highlight and shadow values of PMK and Pyrocat-HD negatives, bearing in mind that the Blue readings are for silver printing with graded papers, UV for alternative processes.
-----Highlight Reading---Shadow Reading---- DR
Blue 1.67 -------------- .47 ------------ 1.20
UV --2.30 --------------.67 ------------1.63
------Highlight Reading---Shadow Reading---- DR
Blue 1.61 -------------- .45 ------------1.16
UV --1.80 ------------- .62 ------------1.18
Anyone who understand the practicalities of printing with both silver and Pt/Pd will immediately understand the reason why a Pyrocat-HD negative makes a better dual-purpose negative.
None of the above is in any way intended to convince Steve Simmons to switch to Pyrocat-HD from PMK. Persons who develop in trays and print exclusively with graded silver papers have nothing to gain in switching. For all other conditions there might be reason to reconsider.
Opinions are one thing. And not always the best things. Which is why I always say, spare me the opinions, just the facts please.
As a matter of fact Sandy, I am working on the article as we "speak". I am comparing head to head, Pyrocat HD, PMK and WD2D (old formula) with FP4 for silver printing on Grade 2 paper.
I will not add anything to Sandy's excellent explanation. I will only add, that using strict impartial experimental controls, so far Pyrocat HD is demonstrating to be the best and most versatile developer of the three. Better and finer grain structure, better tonal rendition and and less b+f when developed to the same CI. Of course, the proof is always in the print and there will be some of those also.
In a previous message I wrote:
"Result: The resolving power of the 90mm Fujinon EBC lens approached 100 lpm with both PMK and Pyrocat-HD negatives. Clearly the limitation to resolving power was in the optical system and/or film, not in developers."
Based on a second and very careful observation of the samples I am going to modify the above statement. My conclusion now is that the Pyrocat-HD samples resolved on average about 5 lpm more than the PMK samples.
I grant that resolving power of this small a magnitude could result from film flatness issues, but it seem unlikely that this factor would have consistently favored the Pyrocat-HD negatives.
BTW, it is precisely because of film flatness issues that I favor testing for resolution with roll film cameras over large formt cameras. My experience is that the differences in T-dimension of differnt film holders, usually of no practical consequence in real life picture taking situations, provides contradictory results in testing conditions where the tolerances are more demanding.
Sandy, as for the versitility of agitation verses minimal or no agitation and PMK, I have a reference article that was written by our own Patrick Gainer in the Nov/Dec 2002 issue of PHOTO Techniques. PMK seemed acording to his testing proved to do very well with minimal and no agitation.
I personally have used both developers. I found no discermnable difference. I just prefer using the one I had a large stock of which is PMK. It's like you say, you go with what you know and feel comfortable with.
Absolutely agree with you. Use what you know and understand best.
I am familiar with Patrick Gainer's article in Photo Techniques on the use of PMK with stand agitation. And Patrick is certainly very knowledgeable on questions of developers and film developing procedures.
However, both Gordon Hutchings and John Wimberley, who are responsible for the two best pyrogallol developers in use today, are very specific in their recommendations regarding the importance of frequent agitation cycles with PMK and WD2D. See pages 20 and 21 (1991 edition) of Hutchings' The Book of Pyro about the importance of frequent agitation cycles. And note that Wimberley recommends agitation at thirty second intervals.
Since both Hutchings and Wimberley insist on the importance of frequent agitation cycles, and given their considerable experience with pyrogallol based developers, my initial inclination is to assume that they know what they are talking about. Granted, I too have experimented and had some limited success with pyrogallol developers using minimal agitation procedures, but I have also seen some uneven staining in other similar experiments.
But, on anothe subject, really love your photo of the legs. Playful, enigmatic, and awfully well done.
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I took Gordon's workshop back in Dec. of 2002 also. He did suggest that we needed to agitate frequently, but what we settled on then was 5 sec. every 45 sec. All workshop negatives came out fine. I know once I got to talking (as if I am ever quiet) and forgot to agitate my tank once. I agitated once in the 8 minutes I was developing the film for. It came out fine. Scared me to death that I had ruined that roll. I just think that there has not really other than Patricks article any real experimentation on the stand development of PMK. I'm just to darn cheap to waste a few rolls to test it.This is why I rely on most here to do that part of it.
BTW, are you going to the LF conference in Monterey? If so bring the comparison prints. I would like to see them (and not to put you donw either. I just would like to see what differences you came up with)
Let me respond to a few comments above.
In the early 1980s I tried ABC, PMK, W2D2,and a Pyrocatechin developer forumula that had been around for many years.
Here are my comments
ABC - the grainiest of the three. Significant film speed loss - about 2 stops. There were warnings that the B solution was not stable although I did not use the formula long enough to experience a problem
Pyrocatechin - good for severe contrast scenes and minus development times. Film speed loss of about 1 stop. Dev times were too long, for my taste, for normal and plus scenes. Grain was better than ABC (better means finer). The results were slightly grainier than the next two developers.
W2D2 - this is the formula that got me started using pyrogallol. The addition of the metol gave a more normal film speed and the grain was much finer than ABC.
PMK - this was the best of the four. Essentially normal film speeds (this does not mean mfg speeds but speeds on my films that were essentially the same as what other people were getting with Tri-X, Super XX, etc). I also was able to print the best delicate high values and with good zone 1 densities I also got very good shadow detail and mid-values as well. Perhaps not quite as good for minus scenes as pyrocatechin but so close that I selected this formula because it was much more of a general purpose developer - dev times for normal and plus were much more user friendly. Sharpness was equal to or better than the W2D2 as was sharpness.
For this reason I decided to use this formula and from then on concentrate on my vision and stop looking for the 'best'developer. I have been printing on variable contrast paper for years and have continued to get the samme delicate high values I initially got on graded appers in the early 1980s.
The comment attributed to Hutchings about ABC for contact printing is something people should ask Hutchings directly rather than rely on a 3rd party source. There is some question about whether or not he really feels that way or made such a statement.
With regards to the article in progress by Jorge I have agreed to publish the article in an upcoming issue of View Camera contingent upon the following
receiving the article
having his testing procedure reviewed by people qualified to do so
either pairing his article with one of mine in the same issue or doing a followup in a subsequent issue
Well Steve, I dont want to give it away, but I think you will be surprised with the results I am getting.Specially concerning the properties of Pyrocat HD in comparison with PMK and WD2D.
I am not prepared to state categorically that one can not use minimal agitation procedures with PMK. My current thinking on the matter results not from my own experiments but from the fact that both Hutchings and Wimberlely have been so insistent on the need for frequen agitation cycles with PMK, and the former in particular offers sound reasons why this is important. To quote from Hutchings, "tests have shown that the primary oxidation products of pyro developers have strong staining effects and will leave a path of stained gelatin as they move across the film if the agitation is inadequate." (p. 21, 1991 edition of The Book of Pyro).
But there may be reason to revist the issue. As I mentioned earlier I myself have had some limited success with PMK and minimal agitation. In fact, when I made the tests with Tmax 100 to compare resolution of PMK and Pyrocat-HD I developed both negative sets side by side in tanks on spiral reeds, using exactly the same agitation procedure, i.e. for one minute initially and for ten seconds every three minutes thereafter. And frankly I can see no indication of uneven staining on the negatives developed in PMK. However, to be completely objective I should point out that the test target itself did not contain the large areas of high density that typically serve as the locus from which developer byproducts begin to streak.
I will not be able to attend the large format conference in Monterey. Unfortunately the dates fall near the end of my spring semester when I am always swamped with work at the university.
In fact I myself heard Hutchings make a similar statement about ABC for contact printing at the large format conference you sponsored in Albuquerque year before last.
Originally Posted by steve simmons
However, to be fair it needs to be pointed out that the remark was made in the context of a discussion on contact prnting with AZO and Pt/Pd. These processes require negatives of much greater contrast than negatives meant for silver printing and a very energetic developer like ABC Pyro is much more practical for getting the necessary contrast in a reasonable develoment time. My take on what Hutchings meant by the comment was simply that there are other developers, including ABC Pyro, that are more suitable than PMK for developing negatives destined for printing with AZO and Pt/Pd.