Pyrocat HD vs. PMK Pyro

JackRosa · Sep 30, 2014

Hoping my fellow APUGers will share their experience/insight re: Pyrocat HD vs. PMK Pyro, specifically with 120 size Tri-X, FP4, HP5.

I use VC FB paper for my enlarging.

I have done some testing recently and have mixed emotions. This is probably the result of not developing the test negs properly. I did use a color densitometer and developed the negs so as to obtain DRN = 1.25 (approx.). Not sure how to correctly interpret the densitometer readings as absolute values (stain) but figure the range does not lie, although the more I think about it, the more I conclude the stain (higher in the highlights) may be affecting readings/my interpretations of said readings. Having a heck of a time getting the stained negs to print as Grade 2 or even Grade 2.5.

Thanking you in advance,

bernard_L · Sep 30, 2014

DRN ??
Dynamic range? If yes, that depends both on the film/dev contrast and on the scene contrast. If not, please explain that acronym.

chriscrawfordphoto · Sep 30, 2014

The yellowish/greenish color of the stain in PMK causes contrast to be a lot lower in the highlight tones (because they have more stain) than in the darker tones when printed on VC paper. I love PMK, but I scan my film, since my health problems won't let me work in the darkroom. If I were still wet printing, I don't know if I would like it since I liked using VC paper when I did wet print. Solution is to use graded paper, or scan the film, or use a different developer.

MDR · Sep 30, 2014

Densitometer readings can be a bit off with Pyro dev. Like Chris said the color of the stain results in a lower highlight contrast on VC Paper. You can use a higher Grade not the best idea or use graded paper which isn't affected by the stain. Using Pyro is a bit like using a Yellow filter darker sky etc.... So you have to take this fact into consideration at the picture taking stage. Also in Europe the normal Grade was 3 (Americans tend to print softer Grade 2) so try it with a grade 3 or 3.5 filter which should give you around grade 2 in the sky the rest is unfortunately Grade 3.

Good luck

Rick A · Sep 30, 2014

Pyro negatives are generally easier to print, even when they are a bit thin. I used to use Pyrocat-HD, using PMK Pyro for the last two years. I print on VC paper, the results are wonderful to say the least. I've never used a densitometer, so I couldn't speak to the OP's result much less interpret them. For me, the proof is always in the printing. If you are switching developers, you will need to do a personal ISO test to reestablish a norm for the new combination.

MDR · Sep 30, 2014

I agree with Rick you need to print the image a densitometer reading won't tell you anything especially with pyro dev. Highlight detail is were pyro outshines non-pyro developers no blown out sky hence my Yellow filter comment.

gzinsel · Sep 30, 2014

I think pyro-cat hd is better for me. just my two cents. for the two films mentioned, um. . . . its kinda hard to say definitively that the choice between the two staining developers will make a huge difference. small differences yes, but remember there is no silver bullets in this. I mean, if you choose one of these, you will not come away with being "blown away" by the other! do you see what I mean. Ya, there will be small. slight advantages, if you spend time(alot) Testing. I would personally recommend getting a box of film shoot with one film, one developer. then choose the other brand film and select the other developer. see which PRINTS you like the best. Over all, I think pyro-cat is easier to use.

ritternathan · Sep 30, 2014

Start with Pyrocat for FP4, HP5, and Tri-X in 120, go to the website http://www.pyrocat-hd.com and look at the development page. That is a good place to start. Use it for six or twelve months and see if you are getting what you want. I love FP4 with Pyrocat-HDC/MC, but usually use Xtol or DS-10 for the 400 speed films in 120. If you are printing with VC papers, PMK can be used for extreme contrast, but it can be difficult w/VC papers and normal contrast. Overall, for VC papers, Pyrocat is more flexible. If you search APUG, there should be some comparisons of Pyrocat and PMK with VC papers.

Andrew O'Neill · Sep 30, 2014

Used PMK (rollo version for rotary) about 15 years ago with HP5 sheet film and didn't care much for it. It seemed lifeless (on VC papers) no matter how much I played around with it. Might have had something to do with the greenish stain... This was my experience with it. I know many photographers that love it. Anyways, never touched it again after trying pyrocat-hd.

JackRosa · Sep 30, 2014

DRN = Density Range of the Negative

bernard_L said:
DRN ??
Dynamic range? If yes, that depends both on the film/dev contrast and on the scene contrast. If not, please explain that acronym.

DRN = density range of the negative. In my case: density (zone VIII) - density (zone I)

JackRosa · Sep 30, 2014

Question for Rick

Rick A said:
Pyro negatives are generally easier to print, even when they are a bit thin. I used to use Pyrocat-HD, using PMK Pyro for the last two years. I print on VC paper, the results are wonderful to say the least. I've never used a densitometer, so I couldn't speak to the OP's result much less interpret them. For me, the proof is always in the printing. If you are switching developers, you will need to do a personal ISO test to reestablish a norm for the new combination.

Thanks Rick. Question: why did you switch from Pyrocat to PMK??? And, do you like PMK better?

JackRosa · Sep 30, 2014

Thank you Chris, Nathan, MDR, Gzinsel, Rick, and Andrew for your contributions to this thread.

Rick A · Sep 30, 2014

JackRosa said:
Thanks Rick. Question: why did you switch from Pyrocat to PMK??? And, do you like PMK better?

I ran out of P-cat HD and wanted to try something new. After reading all I could find on staining developers, I settled on PMK because I had read it shows atmospheric fog better than most. I live in an area that experiences lots of fog, and enjoy photographing the effect. It is about double the price of Pcat, just as easy to use. There is some difference in stain color, and IMO no real difference in printing capability. I've been in darkrooms for over 50 years, and tried very few developers, my mainstay has always been D-76, but I prefer PMK with my LF work. I also use Rodinal, always keep a bottle on hand. When I'm finished with these bottles of PMK I may return to Pcat, but only because of price.

Mainecoonmaniac · Sep 30, 2014

I used pyro PMK for years and fell out of the habit of using it. It renders snow like no other developer. I also like it because during the summer months, I don't have to use it at 68 degrees. It sure makes the negs sharper. One thing I didn't care for is using rubber gloves when using Pyro PMK. I've heard it's toxic. I don't know if it's true or not. I opted to use XTOL because it's low in toxicity. I started using it when I was an undergrad and Gordon Hutchings was the guest lecturer in one of my photo classes. I was awestruck by his images printed with his pyro negs.

TheFlyingCamera · Sep 30, 2014

I'm a devoted Pyrocat HD user. I was using PMK Pyro but I got into doing rotary development and PMK oxidizes very rapidly with rotary development, and as others have noted, it is a speed-losing developer. Not so terrible if you're shooting small formats, but when you're dealing with 8x10 sheet film, and you have to give another stop or sometimes two stops of additional exposure just to deal with the developer you're using, let alone compensating for bellows factor, that's a loss I can ill afford. I haven't noticed Thomas' observations with it, but I run my developer at a higher temperature to get the boost I need for Pt/Pd printing. Instead of developing at 68f, I run at 75f, not only for the contrast boost, but also because the coolest water I can get out of my tap in the summer is 75f. That way I don't have to keep a bunch of ice cubes around in my darkroom to balance the temperature of my developer.

Rick A · Sep 30, 2014

Mainecoonmaniac said:
I used pyro PMK for years and fell out of the habit of using it. It renders snow like no other developer. I also like it because during the summer months, I don't have to use it at 68 degrees. It sure makes the negs sharper. One thing I didn't care for is using rubber gloves when using Pyro PMK. I've heard it's toxic. I don't know if it's true or not. I opted to use XTOL because it's low in toxicity. I started using it when I was an undergrad and Gordon Hutchings was the guest lecturer in one of my photo classes. I was awestruck by his images printed with his pyro negs.

The only time I wear rubber gloves is developing with PMK, not really an issue, I probably should wear them any way. Its toxicity is probably overrated in such dilute amounts, definitely avoid contact with concentrates, and definitely a dust mask if mixing dry chems.

DREW WILEY · Sep 30, 2014

You're going to find a lot of varying opinions from dedicated pyro users, sometimes hotly phrased. Some of this debate centers around contact vs
enlargement papers and respective kinds of negatives hypothetically ideal for these differing applications. Since I mainly doing enlargements onto silver papers of various brands (nowadays mostly VC), I've standardized on PMK pyro. It works superbly in both sheet film trays and hand
inversion tanks (not very well for automated rotary processors). I keeps a long long time in the divided A&B concentrates, even with air in the
bottles, and is very predictable and dependable the whole time. It works well on every film I've ever tried it on except microfilms (incl TechPan) and lith films. And maybe I'm just accustomed to instinctively knowing how the yellow-greenish stain works. Pyrocat formulas are very popular, and there must be a logical reason for that. But I didn't like the brownish stain as well, and found that on certain films I got a more conspicuous grain than I prefer. The "watercolor" effect of PMK in HP5 is particularly appealing - superb edge effect but otherwise a seamless blending of grain, though I almost never shoot HP5 in anything smaller than 8x10. But even with small 120 and 35mm films when
it's really important to get as much information onto a small area as possible, PMK does the job for me. Or conversely, when I want a fast
snapshooting film like Delta 3200 I get a wonderful tonality with it, along with a lovely impression of grain, though with some loss of film speed. I've tried a lot of "pyro" formulas just for the fun of it, and even formulated a couple special pyro tweaks myself, but PMK has pretty'
much become my "standard" developer for ordinary shooting (as opposed to specialized lab film developers used for making contrast masks,
color separations, liths, etc).

damonff · Sep 30, 2014

I love PMK Pyro, it's one of my main 3 developers that I've settled on. The others are XTOL and Rodinal (any brand; they're all the same.) The whole process with the gloves and the toxicity (haha) is cool. I use it semi-stand though, usually 30 minutes with a shake at 15. I read initially that you should shake it every 15 seconds and I did that and it worked well but I read on the internet that it is good for stand. I tried it and I like it more that way. Pyrocat went bad on me so I'm probably not going back. It was only about 7 months old.

TheFlyingCamera · Sep 30, 2014

damonff - Pyrocat will go bad in the bottle when partly used (but so will the other pyro developers). There is a solution to this - get the Pyrocat in glycol instead of water. Then it will last a very long time (year+).

Rick A · Sep 30, 2014

TheFlyingCamera said:
damonff - Pyrocat will go bad in the bottle when partly used (but so will the other pyro developers). There is a solution to this - get the Pyrocat in glycol instead of water. Then it will last a very long time (year+).

+1
I had Pyrocat HD in water and it does in fact go very bad after less than a year. You definitely want to get it in glycol.

Patrick Robert James · Sep 30, 2014

I used PMK for a few years before I started using Pyrocat-P around 2005? I think. Neither has ever been my main developer, which has always been Rodinal. As long as you are developing for your purposes they are both fine. Pyrocat-P has been a little better for me for smaller formats. The large format negs I developed with PMK sure are pretty though.

Lots of great images have been done with both.

Terry Christian · Oct 1, 2014

I'm still on my first-ever batch of Pyrocat. Instead of mixing it in water, I mixed it in an antifreeze that is primarily glycol. It has been working over a year now!

palewin · Oct 1, 2014

I've used PMK for a very long time, and Pyrocat HD now for about a month. I find both easy to print, and as far as film speed goes, rate HP5+ at 320 ASA for both, so I'm not seeing a speed difference. But this isn't based on checking densities, just actual printing from the negatives.

The problem I was having recently is mottled open sky on too many of my PMK negatives (tray developed 4x5). Pyrocat is advertised as being less susceptible to mottling, and in my experience this has proven true, so it may become my "go to" developer in the future (fewer "surprises"). But there seemed to be an extra sparkle to the prints made from PMK, so I'm not certain. (The problem is never having absolutely identical negatives to compare, because even when I expose the two sheets in a holder one after the other, as I have been doing to compare the developers, often there is just enough change in lighting in those few moments so that the "sparkle" difference may be subtle lighting differences rather than the different developers.)

I've used PMK for 4x5 and 120 film with equally good results. For 35mm I still prefer D-76 1:1, less grain than PMK. I haven't tried pyrocat with the medium format yet.

DREW WILEY · Oct 1, 2014

If you're getting mottling, it's not the fault of PMK. Must be some other technique-related issue. I've never had it. Never. And I tray develop a lot of different sheet films.

JackRosa · Oct 1, 2014

Thanks Pete

palewin said:
I've used PMK for a very long time, and Pyrocat HD now for about a month. I find both easy to print, and as far as film speed goes, rate HP5+ at 320 ASA for both, so I'm not seeing a speed difference. But this isn't based on checking densities, just actual printing from the negatives.

The problem I was having recently is mottled open sky on too many of my PMK negatives (tray developed 4x5). Pyrocat is advertised as being less susceptible to mottling, and in my experience this has proven true, so it may become my "go to" developer in the future (fewer "surprises"). But there seemed to be an extra sparkle to the prints made from PMK, so I'm not certain. (The problem is never having absolutely identical negatives to compare, because even when I expose the two sheets in a holder one after the other, as I have been doing to compare the developers, often there is just enough change in lighting in those few moments so that the "sparkle" difference may be subtle lighting differences rather than the different developers.)

I've used PMK for 4x5 and 120 film with equally good results. For 35mm I still prefer D-76 1:1, less grain than PMK. I haven't tried pyrocat with the medium format yet.

Thanks Pete for sharing your experience and insight.

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