Pyrocat HD and TMAX 100: Bad combo?

I've had nothing but exceptional results with TMax100 and Pyrocat HD. It's become one of my standard combos for landscape in MF

@GregY that's lovely. Scan from a print, isn't it? Looks gorgeous; that funnel shape/heartbeat is grand - very powerful.

koraks said:

@GregY that's lovely. Scan from a print, isn't it? Looks gorgeous; that funnel shape/heartbeat is grand - very powerful.

Click to expand...

Thank you. I don't own a scanner, so it's an iPhone photo of a print.

I actually like the paper texture!

koraks said:

I'm very skeptical about this qualification. 90 seconds is more than enough (probably about 6x times!) to completely saturate the emulsion with water.

Click to expand...

I posted the results of some testing I did on this a couple years ago (see here). What I found is that pre-washing film longer (e.g., five minutes versus one minute) causes more inhibition to development, which is almost assuredly a water-saturation effect. The exact mechanism is a little unclear (could be a consequence of gelatin swelling, a dilution effect, some combination thereof, etc.), but the results demonstrated that, at least with the film I was using (Tmax 100), total water absorption continues to increase after one minute of pre-washing, and may even continue after five minutes (though, likely at a much lower rate). As a result, I don't pre-wash film unless it's absolutely necessary, and when I do, I keep the pre-wash time at <90 seconds.

koraks said:

To 'neutralize' part B, the compound would have to be so acidic that merely handling the unprocessed film with bare hands would be dangerous.

Click to expand...

I'm not suggesting neutralization in a strictly "acid-base" sense (though, I can understand the confusion). What I'm conveying is a deleterious interaction between one or more components in the film and the developer working solution that severely restrains development, resulting in negatives that have almost no stain or silver density. I'll repeat the experiments when I get back to the U.S. in couple weeks and post a follow-up.

[As an afterthought, it occurred to me that there's a somewhat contentious/competitive history surrounding the various staining developers and some may interpret my post as being a knock on Pyrocat-HD. That certainly wasn't my intention (it's my favorite B&W developer). I'm just highlighting that there appears to be something unique about Tmax 100 in sheet sizes that requires special attention.]

Scott J. said:

The exact mechanism is a little unclear (could be a consequence of gelatin swelling, a dilution effect, some combination thereof, etc.), but the results demonstrated that, at least with the film I was using (Tmax 100), total water absorption continues to increase after one minute of pre-washing, and may even continue after five minutes (though, likely at a much lower rate). As a result, I don't pre-wash film unless it's absolutely necessary, and when I do, I keep the pre-wash time at <90 seconds.

Click to expand...

That's likely the reason, pH has an effect on gelatin swelling, the higher - more alkali - the faster it will swell. Temperature also has an effect, but with B&W generally at 20ºC a short pre-wash won't fully swell the emulsion, particularly with the better hardening in recent years.

Film manufacturers don't recommend a pre-wash. If you give a longer pre-wash you would need to increase development time to compensate.

Ian

Ian Grant said:

pH has an effect on gelatin swelling, the higher - more alkali - the faster it will swell

Click to expand...

Yeah. And a longer wet time, even at neutral pH, will also allow the emulsion to swell more.
But swelling is not saturation. The emulsion saturates within 15-20 seconds or so, max. Swelling can/will increase over time and I can see how this will affect development - although I'd expect that development would be accelerated by swelling since it'll make the emulsion more easily permeable.

Scott J. said:

I'm not suggesting neutralization in a strictly "acid-base" sense

Click to expand...

So what would the mechanism be in relation to bath B? I'm no chemist, but I struggle with the concept of a magical 'something' that manages to impede electron exchange involving OH- ions. It sounds far-fetched. See also my comments on other developers that are seemingly not affected - not to mention the practical issue of plenty of TMX being developed in Pyrocat without issue. I don't argue that you have seen something weird happening, but the hypothesis that it's due to something in the TMX emulsion just doesn't add up the way I see it.

koraks said:

Yeah. And a longer wet time, even at neutral pH, will also allow the emulsion to swell more.
But swelling is not saturation. The emulsion saturates within 15-20 seconds or so, max. Swelling can/will increase over time and I can see how this will affect development - although I'd expect that development would be accelerated by swelling since it'll make the emulsion more easily permeable.

Click to expand...

Swelling caused by the developer itself (no pre-wash) will accelerate development. The term saturated is probably not apt for that 15-20 second time span, yes the gelatin super-coat will have started to swell, saturation will only be when the gelatin of the whole emulsion as swollen to its maximum absorption, which will vary depending on the developer & pH.

Ian

koraks said:

I struggle with the concept of a magical 'something' that manages to impede electron exchange involving OH- ions.

Click to expand...

It might not be as complicated as that. It may be that the lack of development isn't due to something happening (or not happening) in the film emulsion, per se, so much as it's happening in the developer. In other words: There may be a chemical reaction occurring further upstream -- i.e., in the working solution -- such that by the time the developer has begun to penetrate into the emulsion, it has already been degraded. This may be due to a redox reaction of some kind but not necessarily one happening at latent image sites.

koraks said:

See also my comments on other developers that are seemingly not affected

Click to expand...

The use of pyrocatechin makes Pyrocat-HD unlike most developers. If the phenomenon I and others have described is real, my suspicions would tend to lean toward there being an unfavorable interaction with the pyrocatechin. That said, P-HD also contains a small amount of phenidone as a superadditive. Perhaps consumption of the phenidone is enough to incapacitate the developer (i.e., pyrocatechin alone may not be able to generate sufficient density in ~15 minutes).

koraks said:

not to mention the practical issue of plenty of TMX being developed in Pyrocat without issue.

Click to expand...

Well, yeah, but under what conditions? I agree that you can successfully develop Tmax 100 roll film with or without a pre-wash. I also agree that you can successfully develop sheet sizes with a pre-wash. I'm specifically referring to development of sheet sizes without a pre-wash. It seems most P-HD users perform a pre-wash, which may explain why so few of us have directly observed this specific anomaly.

The sheet sizes of this film are distinguished by the addition of a UV-blocking layer (presumably a dye of some kind; the alt-process people know this too well), which is why earlier posts in this thread speculated on the importance of doing a pre-wash before developing in Pyrocat-HD.

Scott, please take this the right way; at this point, an exchange often starts to become a "did not - did too" kind of back & forth and it's not my intention to be pedantic, or to create the impression that I discount your suggestions or your experience with this film/developer combination.

Scott J. said:

There may be a chemical reaction occurring further upstream -- i.e., in the working solution -- such that by the time the developer has begun to penetrate into the emulsion, it has already been degraded.

Click to expand...

I understand; but if you're looking the activator (whose essence is really to provide OH- ions) and the developer (with phenidone doing much of the work and pyrocatechol replenishing it), I'm really struggling to see what kind of interaction or reaction would have taken place as a result of something that is present in the film itself. It would have to be something pretty resolute, quick and complete, and that doesn't seem very obvious to me, especially because of this:

Scott J. said:

The use of pyrocatechin makes Pyrocat-HD unlike most developers.

Click to expand...

it really doesn't; pyrocatechol is chemically very, very similar to hydroquinone:

The only difference is a single hydroxyl group that's shifted two positions. Indeed, they behave so similarly that you can make a staining hydroquinone developer.
Whatever would attack pyrocat and render it virtually inactive, would logically also affect any HQ developer in the same way. It seems very, very unlikely that there's something in the emulsion that very specifically affects only pyrocatechol (but not hydroquinone) and under very specific conditions (but which ones, I wonder?)

Scott J. said:

It seems most P-HD users perform a pre-wash, which may explain why so few of us have directly observed this specific anomaly.

Click to expand...

On the TMX negatives I developed in Pyrocat developers I didn't use a prewash. I was far too lazy for that, LOL!

Scott J. said:

The sheet sizes of this film are distinguished by the addition of a UV-blocking layer

Click to expand...

I think it's in the base itself, in fact. I know; I bumped my head on that as well. Since it doesn't wash out, it's not a dye that's in the emulsion, and since it's so darn persistent, it's also exceedingly unlikely it plays a role in this case, for two reasons: (1) for it to interact with the developer, it must at least be mobile enough to come close to it and (2) a prewash doesn't get rid of this UV blocking 'thing', so the pre-wash wouldn't have prevented it from doing any damage, if this was the responsible agent. Besides, some of the pyrocat-developed TMX negatives I have in my own collection are on sheet film and they most definitely are of the UV-blocking kind.

I know that this doesn't help in explaining things - quite the opposite, and I sort of feel sorry that I can't offer a solution. But I can't, and I really have problems with the explanations offered so far.

koraks said:

it really doesn't; pyrocatechol is chemically very, very similar to hydroquinone:
View attachment 370980View attachment 370981
The only difference is a single hydroxyl group that's shifted two positions. Indeed, they behave so similarly that you can make a staining hydroquinone developer.
Whatever would attack pyrocat and render it virtually inactive, would logically also affect any HQ developer in the same way. It seems very, very unlikely that there's something in the emulsion that very specifically affects only pyrocatechol (but not hydroquinone) and under very specific conditions (but which ones, I wonder?)

Click to expand...

Yes, but while very similar the tanning and staining effects are of the two developing agents are quite different.

It may well be that a film given a long pre-soak doesn't allow fast enough diffusion of developing agents into the emulsion in the initial stages of development, and the tanning effects on the emulsion closer to the gelatin super-coat has an inhibiting effect.

Hans Windisch's Pyrocatechin Compensating developer exploits rapid tanning in highlight areas.

Ian

Scott J. said:

pyrocatechin alone may not be able to generate sufficient density in ~15 minutes).

Click to expand...

Ian Grant said:

Hans Windisch's Pyrocatechin Compensating developer...

Click to expand...

Hi,

that's the Pyrocat formula I use - plain Pyrocat without super additives.
I can confirm it gives sufficient density and is not exhausted after 15 min in a small Jobo tank.

I've presoaked TMax films ever since they came out, and in relation to several kinds of pyro (I personally prefer PMK to Pyrocat). Although the visual tan is not as great as with certain other films, particularly older ones, it is still quite effective in terms of highlight control.

koraks said:

Whatever would attack pyrocat and render it virtually inactive, would logically also affect any HQ developer in the same way. It seems very, very unlikely that there's something in the emulsion that very specifically affects only pyrocatechol (but not hydroquinone) and under very specific conditions (but which ones, I wonder?)

Click to expand...

Not necessarily. One way I could see catechol being scavenged in a way HQ would not be is by forming a stable chelate complex with appropriate ions; it is precisely the 1,2 arrangement of the hydroxyls which would allow this. I have no idea if the antihalation or other layers in TMX actually contain any such ions, or if this is indeed the cause of the failed development, but it's at least a conceivable explanation.

GLS said:

Not necessarily.

Click to expand...

Of course there are chemical mechanisms that are selective to catechol. But that still leaves me with:

koraks said:

It seems very, very unlikely that there's something in the emulsion that very specifically affects only pyrocatechol (but not hydroquinone) and under very specific conditions (but which ones, I wonder?)

Click to expand...

There's always a theoretical possibility. That still doesn't make it practically likely.

koraks said:

That still doesn't make it practically likely.

Click to expand...

I agree. Doesn't make sense that only TMX would exhibit this behaviour. I can't remember if I've ever developed it with Pyrocat-HD without doing a pre-wash though. I think probably not.