PMK verses Pyrocat-HD
can someone explain the difference in print obtained between these two developers.
Assume Identical subject taken at the same time and boh printed on graded paper (NOT vc paper).
Also assume that testing was done to fit the neg development to the paper.
So what I'm really asking here, is do both developers give an even spread of contrast on graded paper or does one of them favour highlight separation or shadow separation or one shadow separation and the other highlight separation or what?
Also is one less or more grainy although I don't think that will be a problem with either and which one gives sharper images.
Infact will I see any difference between the two?
I've not done complete scientific tests, but here are my observations: (I go bywhat looks good) PMK does best with graded papers; HD works on graded AND VC because of the difference of the stain color.
I would say they are even in all other regards.
Please review the archives. There is extensive and often heated debate around these issues.
My advise is try both of them. The chemicals are cheap and your particular way of working may influence which one ends up being better suited for you.
I've read most of the threads on this and they all discuss about VC printing or film speed or mottling or stain colour etc etc but I found none which answer my question, so if you can point me at one that does, I would appreciate it.
I used PMK for over 7 years before I tried Pyrocat HD. The color of the stain is one variable (PMK is a decidedly green to yellow tint and Pyrocat HD is more of a brown stain) I believe that PMK may be more grainy than Pyrocat HD for smaller formats. Some may take issue with that last statement but it is my opinion. Both are sharp developers. The stain in PMK is a general overall stain that for some processes may be hard to print thru and that was one of the considerations Sandy King worked on when he was working on the formulations of Pyrocat HD. The stain seems to be contained in the image and d min seems to be clear. The last thing is PMK seems more likely to exhaust in a continual agitation situation (like a jobo). Pyrocat HD is good with continual agitation. For my applications (graded and VC paper) I choose Pyrocat HD. Good Luck on which ever you choose.
PMK is not as good with continuous agitation, I agree.
PMK keeps longer as a stock solution. I have had it keep seven years with no reduction in activity. Some speculate it will keep much longer than this. Pyrocat-HD has a relatively short life (about six months, perhaps twelve) once mixed. This is not an awful life compared to many stock solutions but it is not as impressive as PMK.
I like both developers. I tend to use PMK far more because the longevity is important to me (I tend to develop batches of film many months apart). I do find that PMK negatives are often much easier to print on VC paper than negatives developed with traditional developers, so in my experience, PMK certainly is compatible with variable contrast papers.
I see two errors in previous posts. The stain in PMK is not an overall stain, though it may have an overall component if used as originally proposed in The Book of Pyro. Even when it has an overall component, it also has a component that is proportional to the silver density.
Second, none of the Pyrocat series need be short lived. The A solution can be put up (as we say in canning vegetables) in propylene glycol by the substitution of a small amount of ascorbic acid for the sulfite. It then lasts as long as you want to keep it. You will probably want to use it, though, before you get senile.
If the color is the decider, you can use pyrogallol in the same formulation as Pyrocat, but use 2/3 as much. It also is quite soluble in glycol.
In some respects, the Pyrocat series is more versatile than PMK, but that is a matter of opinion, as is just about everything we photo nuts do.
Originally Posted by gainer
Are you referring to the after-bath here or is there something else in the instructions that leads to more general stain?
Gordon Hutchins no longer recommends the after bath with PMK. According to Mr Hutchins the after bath only adds to the general stain and is not really needed.
It is true that PMK has more general stain than Pyrocat-HD (it depends on the film) but there assuredly is image-proportional stain. An article in a magazine (Darkroom Techniques?) a few years ago demonstrated this. You can bleach the silver image out of the negative and still print the image, using only the pyrogallol-produced stain.
I too have abandoned the after-bath. I think the after-bath tends to increase general stain moreso than image stain. I also have noticed no difficulty in attaining good stain after abandoning it, although I use an all-alkaline process which surely helps.
I stand corrected on Pyrocat-HD's longevity. I'll order some propylene glycol and make up a batch this way and see how it fares.