Pyrocat HD vs MC

Dave Krueger · Jul 31, 2006

I've decided to give Pyrocat a try. I noticed the two versions on Photographer's Formulary, but am not clear about the benefit of each.

From what I gather, MC is an improvement over HD in the sense that it has slightly shorter development times, lower general stain, and no phenidone.

I understand why someone would want to stick with something they're familiar with, but I'm using pyrocat for the first time, so I would be interested in knowing if there is a reason for starting with HD instead of MC.

By the way, I did post this elsewhere and someone mentioned that HD, having been around longer, has a bigger knowldge base in terms of its widespread use. That would certainly be a reason worth considering.

I'd appreciate any other comments.

-Dave

[EDIT] I reposted this over in the B&W forum where it belongs.

Tom Hoskinson · Jul 31, 2006

Dave, try an Apug search on Pyrocat MC and another on Pyrocat-HD.

For example, take look at this thread

(there was a url link here which no longer exists)

...I agree with Tom in that the -MC gives slightly higher effective film speed. It also gives slightly lower general stain with very long development times.

sanking · Jul 31, 2006

Dave Krueger said:
I've decided to give Pyrocat a try. I noticed the two versions on Photographer's Formulary, but am not clear about the benefit of each.

From what I gather, MC is an improvement over HD in the sense that it has slightly shorter development times, lower general stain, and no phenidone.

I understand why someone would want to stick with something they're familiar with, but I'm using pyrocat for the first time, so I would be interested in knowing if there is a reason for starting with HD instead of MC.

By the way, I did post this elsewhere and someone mentioned that HD, having been around longer, has a bigger knowldge base in terms of its widespread use. That would certainly be a reason worth considering.

I'd appreciate any other comments.

-Dave

Dave,

Qualities that Pyrocat-HD and -MC share in common. Good emulsion speed, moderately fine grain, high acutance, economical to use, easy to mix.

Plus to Pyrocat-HD. Very large user base that results from almost a decade of being on the market. Proven record of good results with a many films and format, very high acutance with minimal agitation procedures. Lots of good information on this subject on the AZO forum and in the two article Steve Sherman published in View Camera. In this use it has a record of performance that compares favorably with, or beats, the very best stand developers, including Rodinal.

Plus to Pyrocat-MC. Because of the small number of users to date, comments are tentative. However, Pyrocat-MC appears to give higher acutance with continuous and normal agitation than Pyrocat-HD, and gives low B+F with a very high stain intensity with UV sensitive processes.

Pyrocat-HD can be mixed in either water or glycol. No difference in results but the glycol version has better shelf life. Pyrocat-MC must be mixed in glycol (because it contains no preservative). However, if a person wants to mix their own Pyrocat, the Pyrocat-M version, which uses the preservative sulfite in place of ascorbic, gives results that are virtually identical. For more information, see the long thread on Pyrocat M in this forum.

Hope this answers some of your questions.

Sandy

David A. Goldfarb · Jul 31, 2006

I've merged both threads into this one and deleted the posts about the thread.

Dave Krueger · Jul 31, 2006

David A. Goldfarb said:
I've merged both threads into this one and deleted the posts about the thread.

Oh! For a sec I though there was a wholesale bloodbath since I was here last and you just deleted all the violent posts. haha!

Anyway, thanks for combining them.

-Dave

Dave Krueger · Jul 31, 2006

sanking said:
Dave,

Qualities that Pyrocat-HD and -MC share in common. Good emulsion speed, moderately fine grain, high acutance, economical to use, easy to mix.

Plus to Pyrocat-HD. Very large user base that results from almost a decade of being on the market. Proven record of good results with a many films and format, very high acutance with minimal agitation procedures. Lots of good information on this subject on the AZO forum and in the two article Steve Sherman published in View Camera. In this use it has a record of performance that compares favorably with, or beats, the very best stand developers, including Rodinal.

Plus to Pyrocat-MC. Because of the small number of users to date, comments are tentative. However, Pyrocat-MC appears to give higher acutance with continuous and normal agitation than Pyrocat-HD, and gives low B+F with a very high stain intensity with UV sensitive processes.

Pyrocat-HD can be mixed in either water or glycol. No difference in results but the glycol version has better shelf life. Pyrocat-MC must be mixed in glycol (because it contains no preservative). However, if a person wants to mix their own Pyrocat, the Pyrocat-M version, which uses the preservative sulfite in place of ascorbic, gives results that are virtually identical. For more information, see the long thread on Pyrocat M in this forum.

Hope this answers some of your questions.

Sandy

Thanks, Sandy. I'm interested in keeping qualities since I am not a prolific shooter. I actually ordered both, so I may experiment with them side by side. I did order the glycol version.

It's the lower B+F that made me think the MC might be better. The word fog just seems evil to me. haha!

I am primarily interested rotary developing for sheets and intermittent small tank agitation for MF and 35mm. I also plan to compare it with Xtol which seems to be a popular choice from what I've read in various forums. Eventally will try at least the semi-stand method with the pyrocat just because I'm curious about the effect.

I came across the thread on pyrocat M earlier, but will go back and spend more time reading through it.

Thanks again for the comments.

-Dave

Dave Krueger · Jul 31, 2006

Tom Hoskinson said:
Dave, try an Apug search on Pyrocat MC and another on Pyrocat-HD.

For example, take look at this thread

(there was a url link here which no longer exists)

...I agree with Tom in that the -MC gives slightly higher effective film speed. It also gives slightly lower general stain with very long development times.

Ah-ha! I had a look at that thread when you posted it and then forgot how I got there. Friggin old age. LOL! Anyway, I did check out and will revisit it.

I remember wondering if there's something about the forum that automatically makes all occurances of pyrocat show up in a red font. haha!

It's the lower general stain that caught my eye about the MC. But, I actually like the slightly longer development times of the HD because I have some tanks that drain and fill very slowly. I like keeping development times higher for that reason.

-Dave

Jeremy · Jul 31, 2006

And then there's also Pyrocat-P which is supposed to give closer to the edge effects of Pyrocat-HD in stand/semi-stand, but in constant agitation (i.e. tray or rotary processing). The cost is larger grain, but with LF who really cares that much?

This is all gleaned from a couple of different posts here on Apug, but as PF said my p-Aminophenol shipped today I'll be trying it out soon. I'm also curious to see what the p-Aminophenol does with night shots on 120 Fomapan100....

sanking · Jul 31, 2006

Dave Krueger said:
aha!

It's the lower general stain that caught my eye about the MC. But, I actually like the slightly longer development times of the HD because I have some tanks that drain and fill very slowly. I like keeping development times higher for that reason.

-Dave

Dave,

Both Pyrcat-HD and Pyrocat-MC will give very low B+F stain with normal development times for silver printing. Pyrocat-MC has a slight advantage with the very long development times we need for alternative negatives.

If you want to actually increase develoment times for some reason, try a 1:1:150 dilution of Pyrocat-HD and add about 50% to recommended development times for normal processing.

Not sure how much literature you have read about staining developers, but I recommend Gordon Hutchings The Book of Pyro and my article at http://unblinkingeye.com/Articles/PCat/pcat.html Both sources will expand your knowledge of this class of developers.

Sandy

Dave Krueger · Aug 6, 2006

Test results

Well, I used the payrocat HD and MC today as well as xtol. I just developed identical sheets of film in each developer. Amazing how similar the negatives were to each other.

They were all developed in a jobo drum with a unicolor motor base. The xtol and HD negatives printed almost exactly the same. The HD needed 14.5 sec versus 13.5 for the xtol, which squares with the slight increase in film speed from the HD. Contrast was the same between the two. I print with a chromega head on Ilford MG paper and I had dialed in 25M filtering which is close to normal considering the lamp I use. I increased the developing time by 35% per the data sheet for printing on variable contrast paper.

I was pleased with both.

The MC was a different story. The negatve was apparently fogged or something, so I repeated the MC with a new piece of film but this time used distilled water instead of tap water and increased the presoak from 2 to 5 miniutes. The second one looked good, but printed about a quarter grade lower contrast than the HD or xtol. It was a noticably flatter print. Of course, the HD and xtol negs used tap water and had a 2 miniute presoak, so there are multiple variables that could account for the difference. In any case, increasing the filtration to 40M brought the contrast on the MC print up to or slightly above the other two.

Overall, I kinda liked the HD more than the MC, but the differences between all three were so inconsequential (to me, anyway) that I'm not sure which one I'll ultimately settle on. I think those brown negatives could take some getting used to. Brown isn't my favorite color... LOL! I see a little more experimentation in my future, though...

-Dave

sanking · Aug 7, 2006

Dave Krueger said:
Well, I used the payrocat HD and MC today as well as xtol. I just developed identical sheets of film in each developer. Amazing how similar the negatives were to each other.

They were all developed in a jobo drum with a unicolor motor base. The xtol and HD negatives printed almost exactly the same. The HD needed 14.5 sec versus 13.5 for the xtol, which squares with the slight increase in film speed from the HD. Contrast was the same between the two. I print with a chromega head on Ilford MG paper and I had dialed in 25M filtering which is close to normal considering the lamp I use. I increased the developing time by 35% per the data sheet for printing on variable contrast paper.

I was pleased with both.

The MC was a different story. The negatve was apparently fogged or something, so I repeated the MC with a new piece of film but this time used distilled water instead of tap water and increased the presoak from 2 to 5 miniutes. The second one looked good, but printed about a quarter grade lower contrast than the HD or xtol. It was a noticably flatter print. Of course, the HD and xtol negs used tap water and had a 2 miniute presoak, so there are multiple variables that could account for the difference. In any case, increasing the filtration to 40M brought the contrast on the MC print up to or slightly above the other two.

Overall, I kinda liked the HD more than the MC, but the differences between all three were so inconsequential (to me, anyway) that I'm not sure which one I'll ultimately settle on. I think those brown negatives could take some getting used to. Brown isn't my favorite color... LOL! I see a little more experimentation in my future, though...

-Dave

Dave,

Very interesting report. I am tryng to get my mind around why the HD and Xtol negative printed almost exactly the same but the MC negative printed with less contrast. I think I kow the answer, but before I venture my opinion would you please describe the scene you photographed? Low, normal or high contrast? Also, do you notice any difference visually in the intensity of the stain with -HD and -MC? I am guessing that the intensity is greater with -MC?

Sandy

Dave Krueger · Aug 7, 2006

sanking said:
Dave,

Very interesting report. I am tryng to get my mind around why the HD and Xtol negative printed almost exactly the same but the MC negative printed with less contrast. I think I kow the answer, but before I venture my opinion would you please describe the scene you photographed? Low, normal or high contrast? Also, do you notice any difference visually in the intensity of the stain with -HD and -MC? I am guessing that the intensity is greater with -MC?

Sandy

Here is the scene:

http://www.kruegerphoto.com/pyrotest.jpg

I'm looking at the shadow detail inside the garage (through the windows) versus the brightness of the highlights of the gable. For the same shadow tones, the MC print was noticably darker in the highlights.

I was pretty accurate in measuring chemicals, but there was a difference in the water (tap water for the HD vs. distilled for the MC) and the presoak time (2 min for the HD vs. 5 min for the MC).

What I'm wondering about is the oxidation from the rotation of the Jobo 2336 drum on the unicolor motor base. I have no idea how it compares to other rotary processors in terms of rotation speed.

Is the MC more likely than HD to suffer from that effect?

In terms of the intensity of the stain, the MC has more color to it, but the HD negative seems to have a little more silver density.

sanking · Aug 7, 2006

Dave Krueger said:
Here is the scene:

http://www.kruegerphoto.com/pyrotest.jpg

I'm looking at the shadow detail inside the garage (through the windows) versus the brightness of the highlights of the gable. For the same shadow tones, the MC print was noticably darker in the highlights.

I was pretty accurate in measuring chemicals, but there was a difference in the water (tap water for the HD vs. distilled for the MC) and the presoak time (2 min for the HD vs. 5 min for the MC).

What I'm wondering about is the oxidation from the rotation of the Jobo 2336 drum on the unicolor motor base. I have no idea how it compares to other rotary processors in terms of rotation speed.

Is the MC more likely than HD to suffer from that effect?

In terms of the intensity of the stain, the MC has more color to it, but the HD negative seems to have a little more silver density.

Dave,

I think the issue is simply that the -MC negative has a higher intensity stain in the highlights, and the stain is more yellow than the brown stain of -HD. That reduces contrast with VC papers because of the compensating effect of the stain.

Pyrocat-HD works much more like a traditional developer with VC papers because the brown stain does not allow as much green light (to which the low contrast layer of VC papers is sensitive) to pass as does the more yellow/brown stain of -MC.

This is speculation, but the speculation is based on some testing and a few facts.

Sandy

Dave Krueger · Aug 7, 2006

sanking said:
Dave,

I think the issue is simply that the -MC negative has a higher intensity stain in the highlights, and the stain is more yellow than the brown stain of -HD. That reduces contrast with VC papers because of the compensating effect of the stain.

Pyrocat-HD works much more like a traditional developer with VC papers because the brown stain does not allow as much green light (to which the low contrast layer of VC papers is sensitive) to pass as does the more yellow/brown stain of -MC.

This is speculation, but the speculation is based on some testing and a few facts.

Sandy

That could explain it. The stain color is definitely more yellow with the MC; enough to make the difference in my opinion. That actually chalks up one point on the HD side of the board since I only do variable contratst printing and would prefer the slightly better highlight tone separation of the HD.

Thanks for taking the time to respond to my questions and evaluate my results. I will continue with some additional experimentation. I want to try the stand or semi-stand processes at some point.

-Dave

Pyrocat HD vs MC

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