Processing 510 Pyro & 100TMX with Jobo CPP-2

[Salmo22]

For several years now, I've developed 99% of my 4x5 negatives (FP4) in Ilford Ilfotec DD-X using the Stearman SP-445 tank system. I am in the process of transitioning to a Jobo CPP-2 Processor with a couple of 3006 Series Expert Sheet Film Drums. While the Stearman SP-445 has been nearly foolproof for me, the Jobo gives me some options the Stearman just can't. As part of this transition, I want to try a new film developer combination in the Jobo. Tmax 100 developed in 510 Pyro. Jay DeFehr tells me this is a wonderful film/developer combination. Jay's wonderful portraits attest - https://flic.kr/p/BKmMm7

I've found some online information on process times for 100TMX and 510 Pyro, but wanted to seek input from those on the LFPF that have experience with the Jobo system + 100TMX + 510 Pyro.

Thanks in advance.

[Alan9940]

No personal experience with that exact combo of film & developer, but the technical information I have from Zone Imaging (purveyors of 510-Pyro across the pond) is: 8:50 at 21C, standard 1:100 dilution, EI 100.

[Jim Noel]

I never use the Jobo with 510 Pyro. In my mind, it works better in a tray. If you want to try a pyro based developer in a Jobo, look at Pyrocat HD or one of its derivatives.

[martiansea]

I successfully processed 8x10 in a Jobo style tank with PMK, but this was with a hand roller, and I would pick it up and slosh it back and forth vigorously several times a minute to keep from getting streaks, in addition to the constant rolling. I haven't used 510 pyro, but if it's prone to streaking the same way PMK is, I think the motorized rolling of the CPP-2 won't be sufficient agitation. Like Jim said, a different version of pyro would probably be a better choice. I've used Pyrocat HD with the hand rolling and didn't include the additional vigorous agitation, rolling only, and I didn't get streaks.
But this isn't with the Expert Drum, it was with the other style roller tank. I've use an Expert Drum before, but only with C-41, so I can't comment how it performs with pyro.

[Michael Kadillak]

I continue to be amazed at photographers that for some strange reason desire to change two variables in their process at the same time. If you rightfully state that what worked for you for several years - DD-x and 100 TMX and add that the JOBO offers you more options (I suspect more process volume), why not take the intermediate step and singularly introduce the JOBO into your process with DD-X ? My concern is as previously stated that pyro based developers generally speaking are at their best in a tray. Pyrocat (catechol) is an exception. I have tray developed with pyro for many years and it works great. Additionally 100 TMX is a renown fickle film for developing as the JOBO and Kodak's T Max developer are touted as the optimal pairing for the task at hand. DD-X would work fine. I always recommend never change more than one variable in your process (either field exposure or darkroom) because it is inherently manageable as a one variable challenge, but if this is your mission good luck.

[Alan9940]

I have processed many sheets of 4x5 and 8x10 Foma 100 and Ilford FP4+ in Expert Drums on my CPP-2 with Pyrocat-HD, PMK, and 510-Pyro with no issues. I run it at the slowest speed and, with PMK, I change out for fresh developer halfway through the development time.

[koraks]

I used 510 pyro for a short period of time, but ceased doing so for the following reasons:
* Oxidation of the concentrate turned out far worse than online reports indicated, resulting in unpredictable activity once the concentrate was more than a couple of weeks old
* Tendency towards uneven development especially when doing sheet film in rotary drums (Jobo 25xx, not Expert Drums); similar to Pyrocat which is also somewhat prone to this issue, but 510 was far worse as I recall; the problem usually is most visible along the long edges of 4x5's
* Inherent toxicity of the materials used
* End result in terms of tonality and grain was not quite as nice to my eyes as instant mytol (DIY one-shot XTOL variant, which happens to be relatively non-toxic to boot)
* Syrupy concentrate was difficult to pull up into a syringe or pipette and took more time than I liked to dissolve in water (other liquid or quasi-liquid concentrates dissolve far better IME)

Initially I quite liked the results from it, but I ended up favoring instant mytol, which is a bit more work to mix, but otherwise seems to have virtually only advantages...

[Alan9940]

Seems like we all have different experiences with various products... With 510-Pyro, specifically:

* I've used the stock solution when it's the color of India ink without issue
* Never had uneven development in Expert Drums on my CPP-2 or various 4x5 inversion tanks
* Many of the chemicals we all use in our daily lives are toxic
* Never used Mytol, but I've never been unhappy with resulting prints and grain is not an issue for me
* I use syringes that are made for children's syrupy medicine which makes it easy to dispense the concentrate

I will say that when the concentrate is dispensed into water it requires more stirring than any other developer I've ever used. I stir it somewhat slowly (to minimize oxidation) for a few minutes.

[Michael R]

True, we encounter toxic substances all the time, however the dose makes the poison. Pyrogallol is a dangerous compound, and few home-brewers know what they are doing.


Seems like we all have different experiences with various products... With 510-Pyro, specifically:

* I've used the stock solution when it's the color of India ink without issue
* Never had uneven development in Expert Drums on my CPP-2 or various 4x5 inversion tanks
* Many of the chemicals we all use in our daily lives are toxic
* Never used Mytol, but I've never been unhappy with resulting prints and grain is not an issue for me
* I use syringes that are made for children's syrupy medicine which makes it easy to dispense the concentrate

I will say that when the concentrate is dispensed into water it requires more stirring than any other developer I've ever used. I stir it somewhat slowly (to minimize oxidation) for a few minutes.

[Alan9940]

True, we encounter toxic substances all the time, however the dose makes the poison. Pyrogallol is a dangerous compound, and few home-brewers know what they are doing.

When mixing any developer formula containing toxic chemicals like pyrocatechin, pyrogallol, etc, I always wear an apron, nitrile gloves, eye protection, and a good quality respirator. And, I try to mix outside, if possible.

[Michael Kadillak]

I also use a respirator when I tray process with pyro simply because it is an acidic developer that can emit an odor no different than when I mix stop bath from glacial acidic acid. The concentrations are dissimilar, but the concept is the same. With pyrocat the dilution used are so minor that the respirator is not necessary. A gallon of pyro will get me thee months of use whereas I can get as much as 18 months plus out of a gallon of pyrocat. And yes, both need to me mixed outdoors with the full suite of protective equipment listed above.

[interneg]

Pyrogallol is a dangerous compound, and few home-brewers know what they are doing.

And it has no qualities that cannot be matched by less toxic means. The only reason Kodak had for its use by the 1950s/ 60s onwards was for tanning unhardened matrix emulsions - and even then, they had active research into its replacement there until basic Dye Transfer research ended in the mid 1960s. A lot of the time the current use of pyro and the like seems as much about conspiracist denial of the major manufacturers' very considerable basic research in favour of some sort of bizarre macho performance to patch over artistic (and other) inadequacies via the loudly trumpeted use of a needlessly toxic substance.

[Michael Kadillak]

And it has no qualities that cannot be matched by less toxic means. .

Would be elated at qualifying this assertion as I have put at least a dozen less toxic alternatives to the test over the last 20+ years and nothing even comes close to pyro from my visual perspective. I have come to terms with the reality that its toxicity is easily manageable. But at the end of the day the end justifies the means hence the reason that I continue to use it in large quantities.

[Raghu Kuvempunagar]

* Oxidation of the concentrate turned out far worse than online reports indicated, resulting in unpredictable activity once the concentrate was more than a couple of weeks old


Which grade TEA did you use? Lower grade TEA contains some water which can potentially influence the shelf-life of the concentrate.

[koraks]

Of course there's some water in my TEA. Pure TEA is a solid at room temperature. Do you weigh your TEA by cutting blocks off it or do you pour it without having to heat it first? In case of the latter, there's also water in your TEA.

[interneg]

Would be elated at qualifying this assertion as I have put at least a dozen less toxic alternatives to the test over the last 20+ years and nothing even comes close to pyro from my visual perspective. I have come to terms with the reality that its toxicity is easily manageable. But at the end of the day the end justifies the means hence the reason that I continue to use it in large quantities.

What do you perceive as being the behaviour of negatives developed in pyro (which formulae?) or Pyrocat? Much of Pyrocat's supposed qualities really owe more to being fortuitously coincident with known PQ characteristics than anything special. Added to that, a degree of solvency seems to be important to achieving optimal sharpness with modern (i.e. 1950s onwards) emulsions.

[Michael Kadillak]

What do you perceive as being the behaviour of negatives developed in pyro (which formulae?) or Pyrocat? Much of Pyrocat's supposed qualities really owe more to being fortuitously coincident with known PQ characteristics than anything special. Added to that, a degree of solvency seems to be important to achieving optimal sharpness with modern (i.e. 1950s onwards) emulsions.

The only metric that need be in play is in the print. Pyro and pyrocat HD (in reduced agitation mode) have a discernible edge effect and mid tone separation that is simply unparalleled. At the end of the day the print is all that matters.

[interneg]

The only metric that need be in play is in the print. Pyro and pyrocat HD (in reduced agitation mode) have a discernible edge effect and mid tone separation that is simply unparalleled. At the end of the day the print is all that matters.

Very little of that's likely to be the pyro. Of either sort. The useful pyro effects seem to be largely restricted to emulsion tanning in unhardened emulsions.

It seems (from the available industry literature - at the engineering/ research/ academic level - not the relatively popular market books that come to a halt in disclosable knowledge somewhere between 1950/1960) that in those developers, it's largely Metol exhaustion effects or Phenidone byproducts causing development inhibition that produces the observable edge effects. Adding an effective source of electron replenishment (e.g. HQ/ AA/ HQMS etc - and this seems to work even outside conditions that might be characterised as 'superadditive' - even though superadditivity is not as clear-cut as home-brewers assume once any emulsion addenda come into play) will largely switch off the effect in MQ developers, but can be exploited in PQ type developers to produce radically differing levels of the effect. If you strip out the pyrogallol from various staining developers what you're largely left with are bowdlerised Beutler (which produces high sharpness both microdensitometrically and perceptually) derivatives - or accidentally functional PQ relationships - and that one of the isomers of HQ seems to behave sufficiently like it in specific formulae, just producing a slightly different dye. The research wasn't purely microdensitometric, it involved large quantities of double blind print testing - which found that adjacency effects had to be balanced against granularity - and that extremely strong adjacency effect producing developers (POTA) could produce markedly unpleasant prints. By using non-solvent developers the ability to access the Bromide & Iodide placed in the emulsions to produce sharpness enhancing adjacency effects through development inhibition is left unused as well - and it is in accessing the Br and I that D-76 and ID-11 are able to deliver remarkably sharp results - if basic process controls are instigated. The other aspect that is often ignored is that a pH of around 10 seems to maximise sharpness. If you put all these together, you can zero in on potential candidate developers. In other words, an appropriate ratio of P:Q (or AA etc), some solvency and carbonate buffered to just under a pH of 10.

From microdensitometric study we also know that the visually perceivable effects of anything more than nil agitation effectively boil down to differences in overall contrast with no meaningful impact on sharpness measurable or perceivable (when the experiments are properly controlled) - with possible exceptions for litho film in litho developer in specific situations. In other words all that is happening is that the developers you are using & how you are using them is probably widening your margin of error against overdevelopment for the grade you want to print on and possibly underexposure. I've had enough staining developer outcomes through my hands to feel that it's pretty obvious to me why the manufacturers with large basic research capacity, never mind significant organic chemical synthesis resources, seem to have stopped research on staining developers a long time ago. DIR/ DIAR couplers (and research into how to potentially get similar effects from regular B&W emulsions through new emulsion making approaches) were able to deliver effects that many assume their magical-developer-recipe-silver-bullet is delivering (even though it isn't).

[martiansea]

Metol is also poisonous, in case this conversation is giving anyone the impression it isn't.

[interneg]

Metol is also poisonous, in case this conversation is giving anyone the impression it isn't.

All photochemicals should be treated with care and can be harmful if you are stupid in handling them, but of the regular chemistry you are likely to encounter Pyrogallol is particularly potentially dangerous (skin absorption along with all the other risks). Like unsubstituted PPD, there's not really a good reason to use it (unless you absolutely need to tan an unhardened emulsion).

[Michael Kadillak]

Very little of that's likely to be the pyro. Of either sort. The useful pyro effects seem to be largely restricted to emulsion tanning in unhardened emulsions.

It seems (from the available industry literature - at the engineering/ research/ academic level - not the relatively popular market books that come to a halt in disclosable knowledge somewhere between 1950/1960) that in those developers, it's largely Metol exhaustion effects or Phenidone byproducts causing development inhibition that produces the observable edge effects. Adding an effective source of electron replenishment (e.g. HQ/ AA/ HQMS etc - and this seems to work even outside conditions that might be characterised as 'superadditive' - even though superadditivity is not as clear-cut as home-brewers assume once any emulsion addenda come into play) will largely switch off the effect in MQ developers, but can be exploited in PQ type developers to produce radically differing levels of the effect. If you strip out the pyrogallol from various staining developers what you're largely left with are bowdlerised Beutler (which produces high sharpness both microdensitometrically and perceptually) derivatives - or accidentally functional PQ relationships - and that one of the isomers of HQ seems to behave sufficiently like it in specific formulae, just producing a slightly different dye. The research wasn't purely microdensitometric, it involved large quantities of double blind print testing - which found that adjacency effects had to be balanced against granularity - and that extremely strong adjacency effect producing developers (POTA) could produce markedly unpleasant prints. By using non-solvent developers the ability to access the Bromide & Iodide placed in the emulsions to produce sharpness enhancing adjacency effects through development inhibition is left unused as well - and it is in accessing the Br and I that D-76 and ID-11 are able to deliver remarkably sharp results - if basic process controls are instigated. The other aspect that is often ignored is that a pH of around 10 seems to maximise sharpness. If you put all these together, you can zero in on potential candidate developers. In other words, an appropriate ratio of P:Q (or AA etc), some solvency and carbonate buffered to just under a pH of 10.

From microdensitometric study we also know that the visually perceivable effects of anything more than nil agitation effectively boil down to differences in overall contrast with no meaningful impact on sharpness measurable or perceivable (when the experiments are properly controlled) - with possible exceptions for litho film in litho developer in specific situations. In other words all that is happening is that the developers you are using & how you are using them is probably widening your margin of error against overdevelopment for the grade you want to print on and possibly underexposure. I've had enough staining developer outcomes through my hands to feel that it's pretty obvious to me why the manufacturers with large basic research capacity, never mind significant organic chemical synthesis resources, seem to have stopped research on staining developers a long time ago. DIR/ DIAR couplers (and research into how to potentially get similar effects from regular B&W emulsions through new emulsion making approaches) were able to deliver effects that many assume their magical-developer-recipe-silver-bullet is delivering (even though it isn't).

You can read all of the literature and study this topic all you want. In this instance because the objective net result is aesthetic, the literature can only get you so far. Years ago I similarly choose the "technical" path since it was engrained in me as an engineer. It was a terribly frustrating experience as I literally spent countless hours reading everything I could get my hands on and doing the density testing and plotting up film and paper curves from step chart exposures ad nausium and then trying to take that information into the darkroom. I was a mess and I was ready to throw in the towel. Then I had a conversation with Michael Smith and he encouraged me to ditch the BS with the data and simply make prints and adjust in the darkroom. Changed the game from despair to meaningful upside at each darkroom session. Pyro was one of these physical ah ha moments as well after probably a dozen iterations with developers from Harveys 777 to DDX and all points in between. And the calibrating venue that never lies is the print as it should be.

[interneg]

You can read all of the literature and study this topic all you want. In this instance because the objective net result is aesthetic, the literature can only get you so far. Years ago I similarly choose the "technical" path since it was engrained in me as an engineer. It was a terribly frustrating experience as I literally spent countless hours reading everything I could get my hands on and doing the density testing and plotting up film and paper curves from step chart exposures ad nausium and then trying to take that information into the darkroom. I was a mess and I was ready to throw in the towel. Then I had a conversation with Michael Smith and he encouraged me to ditch the BS with the data and simply make prints and adjust in the darkroom. Changed the game from despair to meaningful upside at each darkroom session. Pyro was one of these physical ah ha moments as well after probably a dozen iterations with developers from Harveys 777 to DDX and all points in between. And the calibrating venue that never lies is the print as it should be.

You could have got to the same end point with ID-11/ D-76. Seriously. I only started to dig into the science when I wanted to know why I was apparently (without any real effort other than baseline exposure and process controls - i.e. a lightmeter, a competent thermometer, bog-standard but consistent agitation technique and timer) readily able to manipulate negs to get more than good sharpness without massive pseudotechnical exposure/ process conniptions and potentially hazardous developers. As I'd suspected from the start, the R&D labs knew their stuff - and that the homebrewing brigade were still stuck blundering around the late 1930s. Basic process control is simple to learn yet apparently far too boring for people obsessed with being artsy in the most dilettante ways - yet the irony is that a (very) basic understanding of the useful bits of process control delivers the most rapid and efficient ways to manipulate visual outcomes (and we're not talking baseline landscape imagery - if you can't do that with a 4x5 camera and a box of HP5+ (or whatever) you may have difficulties falling off a log) across a wide range of expressive methods.

[Michael Kadillak]

You could have got to the same end point with ID-11/ D-76. Seriously. I only started to dig into the science when I wanted to know why I was apparently (without any real effort other than baseline exposure and process controls - i.e. a lightmeter, a competent thermometer, bog-standard but consistent agitation technique and timer) readily able to manipulate negs to get more than good sharpness without massive pseudotechnical exposure/ process conniptions and potentially hazardous developers. As I'd suspected from the start, the R&D labs knew their stuff - and that the homebrewing brigade were still stuck blundering around the late 1930s. Basic process control is simple to learn yet apparently far too boring for people obsessed with being artsy in the most dilettante ways - yet the irony is that a (very) basic understanding of the useful bits of process control delivers the most rapid and efficient ways to manipulate visual outcomes (and we're not talking baseline landscape imagery - if you can't do that with a 4x5 camera and a box of HP5+ (or whatever) you may have difficulties falling off a log) across a wide range of expressive methods.

Therein lies our aesthetic differences. ID11 and D76 were the first alternatives I ditched 20 years ago. I detest the milk toast granularity that it produces. Blahhhh. Seriously. Absolutely zero emotion but a technicians dream result relative to your propensity for data. I gave away a 24 sheet box of HP5 in 11x14 similarly because it was similarly worthless unless you had a perfectly normal exposure and had already optimized the film speed. Only exposed one sheet and I was able to conclude it was a dead dog right out of the box. Nothing like running into maximum negative density as its film curve tops out anything but normal light to drive you to drink. Nobody and I meant nobody uses HP5 unless they are silver printers under normal exposure conditions. I don't waste my time with 4x5. I go full Monty with 8x10 as my point and shoot and 11x14, 8x20 and 12x20 to step it up a notch. If what you do works for you, God Bless you. Send me some prints to elaborate your profound conclusion and prove me wrong. I will do the same.

[koraks]

[QUOTE=Michael In this instance because the objective net result is aesthetic, [/QUOTE]
Uhm, so in fact, the net result is anything BUT objective (hopefully you're not going to make a case for aesthetics having to meet an objective standard!) and that means that any rational discussion on your choice is pretty much precluded. You chose your methods for the good reason that they get you to the point where you want to be with the means that you have at your disposal. For me, that would be good enough. No need to convince you out of using pyro.
And yes, I think do pyro should NOT be the first option to consider if someone starts down the same path of finding their preferred methods and materials. @interneg gives an excellent line of reasoning why it's worthwhile to first give it a go with other, less obnoxious, materials. That is, worthwhile for anyone in the position where you were two decades ago.
There is something magical about pyro for sure. Part of it must be its ability to induce unbounded cell growth in mammals.

[martiansea]

Nobody and I meant nobody uses HP5 unless they are silver printers under normal exposure conditions.
Oh c'mon... I've made good alt prints (Chrysotype, Platinum, etc...) from HP5, and had plenty of density and contrast for it. And I know I'm not the only one.

[Michael Kadillak]

Oh c'mon... I've made good alt prints (Chrysotype, Platinum, etc...) from HP5, and had plenty of density and contrast for it. And I know I'm not the only one.

Yes, as long as you stay within its limited headspace it is absolutely possible to extract a quality print from HP5. All I am saying is factually HP5 does not have the density latitude capability as other sheet films and I do not want to be inhibited with what I choose to photograph in the field with having to be concerned about those factual imitations when I choose to make an image. And I do not need to look at a comparable film curve. All I need to do is try to print a negative that has been unintentionally taken where it does not do well to relegate HP5 to the end of the line. Fortunately, there are a host of more "dimensional" options to consider. FP4+, old version one T Max 400 and even Foma 200 are vastly superior for a photographer that wants optimal flexibility in the field.

[Raghu Kuvempunagar]

Of course there's some water in my TEA. Pure TEA is a solid at room temperature. Do you weigh your TEA by cutting blocks off it or do you pour it without having to heat it first? In case of the latter, there's also water in your TEA.

I use this TEA (http://www.srlchem.com/products/product_datasheet/productId/1241/Triethanolamine-pure--98-). It says purity is 98% and water content is less than 0.5%. It has always remained a viscous liquid and room temperature here is generally 25C and above.

Jay originally used commercial grade TEA (https://www.photo.net/discuss/threads/pyro-question.176020/) which is a mixture (approximately) of 85% TEA and 15% DEA for making 510-Pyro. Later I saw 98% TEA being recommended, but I never saw low freeze grade TEA (one that contains water) for making 510-Pyro.

[tundra]

Uhm, so in fact, the net result is anything BUT objective (hopefully you're not going to make a case for aesthetics having to meet an objective standard!) and that means that any rational discussion on your choice is pretty much precluded. You chose your methods for the good reason that they get you to the point where you want to be with the means that you have at your disposal. For me, that would be good enough. No need to convince you out of using pyro.
And yes, I think do pyro should NOT be the first option to consider if someone starts down the same path of finding their preferred methods and materials. @interneg gives an excellent line of reasoning why it's worthwhile to first give it a go with other, less obnoxious, materials. That is, worthwhile for anyone in the position where you were two decades ago.
There is something magical about pyro for sure. Part of it must be its ability to induce unbounded cell growth in mammals.

A bit over the top. Yes, Pyrogallol is nasty stuff. That's why you wear a lab apron, nitrile gloves, and eye protection when using these developers and additionally a good mask and ventilation when mixing it. If people do not have good lab technique, I advise them against chemical photography entirely since you're supposed to use common sense when handling these materials.

In my lifetime I've done many dangerous things - firing semiautomatic pistols for hours on end, flying light planes over mountains, SCUBA diving at night in the ocean, skiing at high altitudes - but I've done these "dangerous" things very safely because, in every case, I was taught how to do so. The most dangerous thing I have ever done - by far - at least statistically, is to drive my car, especially within a tight radius of my home. At least in the US, automobile accidents kill far more people per capita than guns, accidents, or fires. If we accept the contemporary fears of anything that might hurt us, we should all stop driving ... except that trains are even worse and you cannot fly to work.

It is interesting to note that the folks who sell 510 Pyro in the UK have just had some sort of analysis done that suggests there is no significant environmental or health risk in the concentrate and were able - I am told - to get rid of the associated warning labels:

https://www.5x4.co.uk/threads/revised-safety-data-sheet-for-510-pyro.1909

If people are going to use chemical photography, they need to learn good lab technique, have proper protective equipment and ventilation, and use common sense.

[interneg]

Oh c'mon... I've made good alt prints (Chrysotype, Platinum, etc...) from HP5, and had plenty of density and contrast for it. And I know I'm not the only one.

I'd agree that it's easy to get plenty density & good curve behaviour from HP5+ for high contrast needs if you use appropriate developers (PQ Universal, D-72/ Dektol D-19b, D-11 would be good starting places for most) rather than the hearsay and cant of weekend-workshop-fetishised developers - which either run out of steam and/ or produce ever greater levels of development inhibition as they do so (i.e. the emulsion engineers were very considerably smarter than the 'buy-my-workshop' gurus slowly poisoning themselves with pyrogallol).

Never mind that people apparently don't have a micron of a clue how to manipulate D-76 (anyone who starts jumping up and down and yelling about it lacking 'something' is immediately telling me they've repetitiously screwed up the basics and are hunting for magic bullets - when almost always it's a basic failure of baseline level exposure and/ or process technique - often by alarmingly large margins) - or consider how emulsions were/ are engineered to attempt to rein in the actions of incompetent-end-users-in-potentia-who-have-magazine-columns-or-run-weekend-workshops-or-prominent-social-media-presences.


It is interesting to note that the folks who sell 510 Pyro in the UK have just had some sort of analysis done that suggests there is no significant environmental or health risk in the concentrate and were able - I am told - to get rid of the associated warning labels:

https://www.5x4.co.uk/threads/revised-safety-data-sheet-for-510-pyro.1909

The major manufacturers want to minimise their chances of getting sued & ensure their products can be readily sold worldwide. By those standards, essentially everything in Ilford, Kodak, Adox etc's ranges is considerably safer than 510-Pyro - the major manufacturers are not idiots, but are realists about ensuring their end users take appropriate precautions when handling their products. Everything Mr Lane claims should be treated with extreme care, especially when you can find where he lifted it from in the first place.

[tundra]

The major manufacturers want to minimise their chances of getting sued & ensure their products can be readily sold worldwide. By those standards, essentially everything in Ilford, Kodak, Adox etc's ranges is considerably safer than 510-Pyro - the major manufacturers are not idiots, but are realists about ensuring their end users take appropriate precautions when handling their products. Everything Mr Lane claims should be treated with extreme care, especially when you can find where he lifted it from in the first place.

Well ... that's not really an argument from the objective scientific facts but more of an oblique observation based on law. I'm not saying you are wrong, only that this is besides the point. Deeper pockets always have to be ready for larger lawsuits, which is chemically irrelevant.

It is almost certainly true that Pyrogallol based developers are inherently more dangerous (to humans and animals) than say metol-based developers (though I would note that metol has its own problems with long term exposure). I am less clear that every single product made by Kodak, Ilford, or Adox is guaranteed to be less risky/free of risk. In fact, I seem to recall that Kodak's own HC-110 does/did have a pyro component but that's from memory, I have no first source for this.

Again, good lab technique, protective equipment, and ventilation can be used to mitigate these risks, in my opinion. Anyone not having those at their disposal should run far, far away from using these developers. For that matter, anyone not having those at their disposal should probably stay out of a chemical darkroom entirely as there are all manner of other chemistry that can wreak havoc when mis-used.

[John Layton]

Truly sorry if this might sound pompous to some...but if realizing my vision requires chemistry which might be deleterious to my health (understanding that I do what I can to mitigate these effects)...so be it!

[Michael Kadillak]

Truly sorry if this might sound pompous to some...but if realizing my vision requires chemistry which might be deleterious to my health (understanding that I do what I can to mitigate these effects)...so be it!

Absolutely agree John. After one gets past the chat phase and truly commits oneself to the darkroom and objectively assesses their results ie. what "moves them" visually in mounting and framing a print that they will sign as their "best work", that is where the rubber meets the road. This entails that they have mastered the art of producing a quality negative from which they can work with. Like you I would put on a full body protective lab suit if need be for my chosen soup simply because the resultant print is directly proportional to the negative it is produced from. This is precisely why B&W photography is such an art form in that the vast array of chemical developers we can deploy have an equally enormous effect on the developer/negative interaction. Look at enough prints from the early days of photography to current in concert with what you are producing and the question of your personal choice in developer virtually resolves itself. Then you just need to figure out the safety issues if they exist.

[interneg]

In fact, I seem to recall that Kodak's own HC-110 does/did have a pyro component but that's from memory, I have no first source for this.

Catechol at various points - and in small quantities. It seems safe enough once in solution - and like HQ, I wouldn't bathe in the stuff in very high concentrations (far higher than film developers). All three of the Dihydroxybenzenes seem to have been very well researched by Kodak across a wide variety of uses (including as couplers etc) and further derivatives too - if catechol genuinely had advantages as a developing agent rather than as a scavenger or something like that (I recall) in HC-110, there's no question Kodak would have made use of it (for example, there are components in some emulsions that are used in the order of 7g/ 500kg of emulsion - because they have useful effects - even if they have to be expensively synthesised, so it's not a question of price or some sort of conspiracist nonsense - it's just that it probably offered no advantages over HQ under rigorous testing). From what I also recall, the only reason catechol is used in Pyrocat is because it produces a better stain (a dye coupler really) colour than HQ.

[Michael Kadillak]

Catechol at various points - and in small quantities. It seems safe enough once in solution - and like HQ, I wouldn't bathe in the stuff in very high concentrations (far higher than film developers). All three of the Dihydroxybenzenes seem to have been very well researched by Kodak across a wide variety of uses (including as couplers etc) and further derivatives too - if catechol genuinely had advantages as a developing agent rather than as a scavenger or something like that (I recall) in HC-110, there's no question Kodak would have made use of it (for example, there are components in some emulsions that are used in the order of 7g/ 500kg of emulsion - because they have useful effects - even if they have to be expensively synthesised, so it's not a question of price or some sort of conspiracist nonsense - it's just that it probably offered no advantages over HQ under rigorous testing). From what I also recall, the only reason catechol is used in Pyrocat is because it produces a better stain (a dye coupler really) colour than HQ.

Photography is not a theoretical art form that can effectively be extrapolated from manufacturers literature and wide eyed conjecture. Adjectives like "I also recall" and "seem to have been well researched by Kodak across a wide variety of uses" are completely meaningless in the broader context of meaningful results at the personal level relative to the topic in play. If you feel compelled to support a result that is in line with your "pyro is not what it is cracked up to be" conclusion they do us a favor and show us why you feel this way in the form of some example prints.

[tundra]

Truly sorry if this might sound pompous to some...but if realizing my vision requires chemistry which might be deleterious to my health (understanding that I do what I can to mitigate these effects)...so be it!

In 50 years of doing this, I've had a number of inflection points in which some technical "epiphany" or another opened up my work that translated directly into better aesthetic results:

- Finding out about and learning the baseline of Zone system
- Learning VC split printing
- Discovering how PMK (as an example of Pyro staining developers) could help me master very big SBRs without crushing mid-tone contrast
- Combining Pyro staining (via Pyrocat-HD) and semistand/high dilution development to create astonishingly better negatives and prints

Note that I do not claim that this is the ONLY way to achieve good results, but it was my way. Notice also that these discoveries built upon each other. Notice, most importantly, that the measure of any of these was- and is improving aesthetic output not improving measured data.

The only way the chemistry we're talking about here should remotely put your health at risk is if we're not practicing good, standard, lab precautions. I mean, we're not working with methyl mercury or cyanide gas for heaven's sake. I stipulate that if we are sloppy we can do some medical harm, but even the modicum of care taught in High School Chemistry likely would suffice ... (they DO still teach Chemistry right, or is it all social justice and emotional wellbeing these days???)

[sanking]

From what I also recall, the only reason catechol is used in Pyrocat is because it produces a better stain (a dye coupler really) colour than HQ.

Sorry, that is just not true, and if anyone should know it is me.

In a larger sense, the unique characteristic of tanning and hardening developers is not the stain, but hardening. Staining does have some incidental advantages for printing with VC silver papers, and in crafting negatives that print with different contrast with silver papers and some alternative processes, including pt/pd.

That said, it is hardening that results in more precise reduction, which gives Pyro gives more pronounced edge effects than other developers. This is due to the fact that there is much less migration of silver halide during development as hardening prevents the scattering of light which gives infectious development (spreading of silver development beyond the exact image boundaries. As a result of these effects Pyro is capable of more pronounced edge effects than other developers.

Of course, reduced agitation along with dilution are the keys to masterful use of Pyro staining and hardening negatives, and to that end I suggest farther reading of Steve Sherman's article on the subject, "Altering a Negative's Personality: Reduced Agitation Film Processing, at https://unblinkingeye.com/Articles/RASS/rass.html.

Sandy

[Michael Kadillak]

Sorry, that is just not true, and if anyone should know it is me.

In a larger sense, the unique characteristic of tanning and hardening developers is not the stain, but hardening. Staining does have some incidental advantages for printing with VC silver papers, and in crafting negatives that print with different contrast with silver papers and some alternative processes, including pt/pd.

That said, it is hardening that results in more precise reduction, which gives Pyro gives more pronounced edge effects than other developers. This is due to the fact that there is much less migration of silver halide during development as hardening prevents the scattering of light which gives infectious development (spreading of silver development beyond the exact image boundaries. As a result of these effects Pyro is capable of more pronounced edge effects than other developers.

Of course, reduced agitation along with dilution are the keys to masterful use of Pyro staining and hardening negatives, and to that end I suggest farther reading of Steve Sherman's article on the subject, "Altering a Negative's Personality: Reduced Agitation Film Processing, at https://unblinkingeye.com/Articles/RASS/rass.html.

Sandy

Thanks for the clarification Sandy. I was hoping this reached your radar screen.

[tundra]

Sorry, that is just not true, and if anyone should know it is me.

In a larger sense, the unique characteristic of tanning and hardening developers is not the stain, but hardening. Staining does have some incidental advantages for printing with VC silver papers, and in crafting negatives that print with different contrast with silver papers and some alternative processes, including pt/pd.

That said, it is hardening that results in more precise reduction, which gives Pyro gives more pronounced edge effects than other developers. This is due to the fact that there is much less migration of silver halide during development as hardening prevents the scattering of light which gives infectious development (spreading of silver development beyond the exact image boundaries. As a result of these effects Pyro is capable of more pronounced edge effects than other developers.

Of course, reduced agitation along with dilution are the keys to masterful use of Pyro staining and hardening negatives, and to that end I suggest farther reading of Steve Sherman's article on the subject, "Altering a Negative's Personality: Reduced Agitation Film Processing, at https://unblinkingeye.com/Articles/RASS/rass.html.

Sandy

I fully concur with this. My extensive personal testing last year to find my own optimal semistand and EMA configuration bears this out visibly and beautifully.

[interneg]

That said, it is hardening that results in more precise reduction, which gives Pyro gives more pronounced edge effects than other developers. This is due to the fact that there is much less migration of silver halide during development as hardening prevents the scattering of light which gives infectious development (spreading of silver development beyond the exact image boundaries. As a result of these effects Pyro is capable of more pronounced edge effects than other developers.

In an unhardened emulsion this might be the case. In a vinyl ether hardened emulsion it's going to be questionable at best. What is however known (and can be found in the literature/ patents from the 1970s onwards and hinted at elsewhere) seems to be that Phenidones (better yet, Dimezone-S) can deliver potentially extremely strong development inhibition effects giving the adjacency effects you attribute to Catechol's dye coupler 'stain'. A PQ (or PC or PA) developer with the right ratio of the ingredients with a carbonate buffer should be very readily capable of delivering strong adjacency effects - they optimise in the pH range that carbonate buffers deliver. With modern emulsions, solvency will deliver better sharpness via accessing & releasing Iodide & Bromide (which are regarded in this context as development inhibiting agents) placed in the emulsion(s) explicitly to produce these effects. A great deal of B&W film R&D seems to have concentrated on getting conventional B&W emulsions to deliver something approximating the desirable effects of DIR/ DIAR (and subsequent evolutions - including phenidone releasing variants) couplers in C-41 materials. Most commercial PQ developers (barring a handful like Ilfosol 3) largely seem to have tended to tune down the adjacency effects as double-blind visual testing historically seems to have largely preferred D-76's grain/ sharpness character.

[tundra]

In an unhardened emulsion this might be the case. In a vinyl ether hardened emulsion it's going to be questionable at best. What is however known (and can be found in the literature/ patents from the 1970s onwards and hinted at elsewhere) seems to be that Phenidones (better yet, Dimezone-S) can deliver potentially extremely strong development inhibition effects giving the adjacency effects you attribute to Catechol's dye coupler 'stain'. A PQ (or PC or PA) developer with the right ratio of the ingredients with a carbonate buffer should be very readily capable of delivering strong adjacency effects - they optimise in the pH range that carbonate buffers deliver. With modern emulsions, solvency will deliver better sharpness via accessing & releasing Iodide & Bromide (which are regarded in this context as development inhibiting agents) placed in the emulsion(s) explicitly to produce these effects. A great deal of B&W film R&D seems to have concentrated on getting conventional B&W emulsions to deliver something approximating the desirable effects of DIR/ DIAR (and subsequent evolutions - including phenidone releasing variants) couplers in C-41 materials. Most commercial PQ developers (barring a handful like Ilfosol 3) largely seem to have tended to tune down the adjacency effects as double-blind visual testing historically seems to have largely preferred D-76's grain/ sharpness character.

So, if we stipulate to that, we'd expect to see little- or no pyro-related adjacency (edge/Mackie line) effects. That may be true in theory, I haven't sufficient expertise to comment on the theoretical matters at hand. However, this is what I have seen, in actual fact with real negatives using PMK, and then later Pyrocat-HD, the latter in very dilute, very long development procedure:

1. PMK shows edge effects with some modern films - Tri-X and Agfapan APX 100 leap to mind. I believe both are hardened emulsions.

2. Pyrocat-HD similarly shows edge effects. These are more pronounced with some films (Tri-X, FP4) than others (Agfapan APX 100). It's more pronounced with EMA than semistand in all cases.

3. There's no question that unhardened emulsion seem to love Pyro, though. Efke PL100M, for example, really shows the edge effects and improved acuity of using these developers. I am not sure how Adox CMS 100 II is made, but it seems to like it as well.

If your argument is that a phenidone-based developer could achieve the same/better results with modern films, that may be so, but I've not seen any examples thereof. I have done seminstand with D-23 and highly dilute HC-110 (1:128) and seen some, but not as pronounced such effects.

If you're saying pyro does not have this adjacency effect at all or minimally with modern emulsions, my negatives kindly take umbrage with you.

[interneg]

1. PMK shows edge effects with some modern films - Tri-X and Agfapan APX 100 leap to mind. I believe both are hardened emulsions.

Metol only developers will produce adjacency effects via exhaustion byproducts of Metol. Adding HQ (or similar) in sufficient quantity will switch this off - it's likely that the level of Pyrogallol in PMK's working solution may be such that its impact on the Metol exhaustion process is low enough that it allows adjacency effects to form.


2. Pyrocat-HD similarly shows edge effects. These are more pronounced with some films (Tri-X, FP4) than others (Agfapan APX 100). It's more pronounced with EMA than semistand in all cases.

That's likely largely the Phenidone development inhibition effects rather than anything else. And EMA is nothing special - anything over absolute standstill has been shown repeatedly across long ranges of developer series and microdensitometric study to be merely affecting overall contrast (Litho dot formation is a different matter) - i.e. give your negs the least necessary exposure and least processing time needed to print on the highest grade that you dare & you'll end up at the same point. It just requires a little more in the way of (very basic) process control than the mystical handwaving of EMA. Or you could use a darkroom unsharp mask to produce stronger and more controllable sharpness enhancement effects.


3. There's no question that unhardened emulsion seem to love Pyro, though. Efke PL100M, for example, really shows the edge effects and improved acuity of using these developers. I am not sure how Adox CMS 100 II is made, but it seems to like it as well.

Phenidones (specifically Dimezone-S) may also produce some significant tanning effects too - certainly enough for Kodak to patent their useage in processing dye transfer emulsions - but the reactions causing crosslinking that Lee posits in the aforementioned patent will have no impact on modern well hardened emulsions. And unless you have tested using Kodak D-1 or other developers that do not contain developing agents proven to produce adjacency effects under some conditions (Metol) or potentially under all conditions if correctly used (Phenidones), how do you know that you aren't seeing those effects instead of assuming it must be the coupler forming component?


I have done seminstand with D-23

Too high a level of metol, even at 1+3. Henn evolved D-23 into Microdol, then Microdol-X (Perceptol is the same thing effectively) - which in dilute form is capable of delivering very good sharpness via Metol exhaustion. Beutler is the same idea but taken to a more extreme sharpness aim rather than granularity/ sharpness balance.


highly dilute HC-110 (1:128) and seen some, but not as pronounced such effects.

HC-110 wasn't designed for maximising adjacency effects. The P:Q ratio is important to this.

[bmikiten]

Possibly one of the best developer write-ups I've seen in years! Nice job.

[tundra]

It just requires a little more in the way of (very basic) process control than the mystical handwaving of EMA. Or you could use a darkroom unsharp mask to produce stronger and more controllable sharpness enhancement effects.


Getting unsharp masks to properly align, fiddling with mask exposure, etc. is a whole bunch more time consuming and error prone than EMA. Once EMA is dialed in, there is no real handwaving, just utterly repeatable darkroom practice. I'd suggest that - as a pragmatic matter - unsharp masking is the mystical sauce here.



how do you know that you aren't seeing those effects instead of assuming it must be the coupler forming component?


I don't, but I also don't care. I'm primarily interesting in making silver prints, not lab notes. I realise there is a legitimate place for photochemists and sensiometrists to pursue their disciplines, and I'm certainly not dismissing their work. But I want to make glorious prints. That means eliminating variables, finding *A* process that works (not exploring every possible alternative avenue) in the service of my desired outcomes.

[interneg]

Getting unsharp masks to properly align, fiddling with mask exposure, etc. is a whole bunch more time consuming and error prone than EMA. Once EMA is dialed in, there is no real handwaving, just utterly repeatable darkroom practice. I'd suggest that - as a pragmatic matter - unsharp masking is the mystical sauce here.

You can end up at the same point as EMA claims to do so by using a perfectly normal developer and developing to a low CI, such that you'll need a hard grade to print on - agitation doesn't come into it (other than not using vessels that promote uneven development). If EMA genuinely worked, the major manufacturers would have found out decades ago & marketed the hell out of it - as a matter of fact they studied agitation very deeply, at a level and quality way beyond what anyone has shown any evidence of understanding thereof in this thread.

Masks aren't difficult, just don't overcook them.


I'm primarily interesting in making silver prints, not lab notes.

It's considerably easier to get good prints once you understand that staining developers and EMA are a material and time wasting distraction.

[Michael Kadillak]

It's considerably easier to get good prints once you understand that staining developers and EMA are a material and time wasting distraction.

Sadly this discussion has evolved into a whole lot of unsubstantiated proselytizing that there is no sensible person that need consider pyro as a developer because you have "equivalent alternatives". For the life of me I cannot understand the incentive to take such a theoretical position in the face of a number of individuals (including me) that have 20-30 years of making LF prints and have personally migrated to pyro because of the visually measurable quality it adds to their prints. If you could take off your lab coat for just a short time and show us a legitimate photographic print that supports your conclusions along these lines that would go a long way to substantiating these assertions. Without that hard evidence I will let the future reader draw their own conclusion.

[tundra]

It's considerably easier to get good prints once you understand that staining developers and EMA are a material and time wasting distraction.

I have been a silver printer - better- and worse - for over 50 years. This position on your part is hyperbolic nonsense. I have empirical and evidentiary proof (not supposition) that you're just utterly wrong about this. I have made very satisfying prints from pyro-based EMA negatives (and semistand, and normal development, and other developers and ...)

Note that I've never said there is NO other way to achieve good results - there are, and many other fine photographers use them to great effect. But you've utterly conflated the map and the territory here. You sound like you want argue from a position of science, but claims like this are feeble attempts to argue from authority:




If EMA genuinely worked, the major manufacturers would have found out decades ago & marketed the hell out of it - as a matter of fact they studied agitation very deeply, at a level and quality way beyond what anyone has shown any evidence of understanding thereof in this thread.



Appealing to authority isn't science, it's a logical fallacy.

What I always find is that people who argue as you do - complete certitude, condescension, dismissing any other person's view or actual work - pretty much manage to never show us their prints. So how about it. Let's see YOUR satisfying images. I don't mean your book full of H/D curves or test negatives, I mean actual prints expressing some aesthetic or another.

[tundra]

Sadly this discussion has evolved into a whole lot of unsubstantiated proselytizing that there is no sensible person that need consider pyro as a developer because you have "equivalent alternatives". For the life of me I cannot understand the incentive to take such a theoretical position in the face of a number of individuals (including me) that have 20-30 years of making LF prints and have personally migrated to pyro because of the visually measurable quality it adds to their prints. If you could take off your lab coat for just a short time and show us a legitimate photographic print that supports your conclusions along these lines that would go a long way to substantiating these assertions. Without that hard evidence I will let the future reader draw their own conclusion.

There is a long and painful tradition on the internet that self-anointed experts want to tell everyone else they are wrong because they - the expert - always know better. As you point out, the Internet Expert is always long on provocative and accusatory commentary, but never quite manages to provide any actual evidentiary refutation.

I fully stipulate that there are many ways to get to a compelling print. The idea that one of the ways - one which many of us have use to great effect - should therefore be dismissed, is on its face, and without reservation, absurd.

[Raghu Kuvempunagar]

Hello Lachlan,

There is at least one published research work from 60's which says "a low pH formulation, consisting only of pyrogallol, Phenidone, and sodium sulphite (pH 8.30) yields a higher emulsion speed for the same development time than does a conventional fine grain developer like Eastman Kodak D-76". Further, it describes "a stable, high pH, Phenidone-pyrogallol developer that makes use of ascorbic acid rather than sodium sulphite as the preservative". So 510-Pyro like Phenidone-ascorbic acid-pyrogallol developers were studied and found to have some advantages over D-76. It's another matter that such developers didn't become widely popular back then. And the subsequent progress in emulsion technology might have also negated the advantages.

https://www.tandfonline.com/doi/abs/10.1080/00223638.1966.11737326

[interneg]

Hello Lachlan,

There is at least one published research work from 60's which says "a low pH formulation, consisting only of pyrogallol, Phenidone, and sodium sulphite (pH 8.30) yields a higher emulsion speed for the same development time than does a conventional fine grain developer like Eastman Kodak D-76". Further, it describes "a stable, high pH, Phenidone-pyrogallol developer that makes use of ascorbic acid rather than sodium sulphite as the preservative". So 510-Pyro like Phenidone-ascorbic acid-pyrogallol developers were studied and found to have some advantages over D-76. It's another matter that such developers didn't become widely popular back then. And the subsequent progress in emulsion technology might have also negated the advantages.

https://www.tandfonline.com/doi/abs/10.1080/00223638.1966.11737326

Sulphite = not a staining developer. Levy's work was not driven by pictorial/ aesthetic requirement, but primarily by military/ scientific research need. And if Levy was looking at those recipes, Kodak will have looked at them too. Everyone was trying to improve on D-76 (and understand its mechanisms) for various reasons, but kept falling at the point they had to do double blind print comparison tests. Methods of dealing with AA's Fenton reaction issues were being intensely researched throughout this period - had DTPA or similarly powerful sequestrant been readily available at the time, AA would have come into use industrially in photochemistry in the 1960s/70s if not earlier. It's clear (from later documentation) that Kodak resolved the mechanism of Levy's POTA without disclosing it at the time - and used that knowledge (as did their competitors who were no slouches in the basic science) together with what they seem to have learnt about HQMS' effects (similar behaviour happens with AA, hence it being attractive as an HQ replacement) being preferential to all the other alternatives. A research result does not necessarily equal a viable/ reliable product - but it can count as prior art, and it's worth noting that Levy's earlier work with thickened monobaths was likely patented defensively against Polaroid (and potentially Kodak). And as for TEA, it was used in Dye Transfer at the time (and other processes etc) so it will definitely have been gone over rather thoroughly by Henn etc in getting to HC-110 (along with lots of other permutations that likely failed the desired parameters) - don't assume you are discovering anything new, and rather than desperately trying to dredge up post-facto defences of not-very-well-thought-out staining developers, you could take a few minutes to consider the nature of large scale photographic research at that time of that article - had there been enough evidence that under rigorous visual test conditions pyrogallol really had advantages over HQ or AA, there would have been concerted efforts to make use of it. Instead, Kodak were patenting ways to eliminate it from the process that relied on it - via the use of Dimezone-S and AA. Contemplate why that might have been.

[Raghu Kuvempunagar]

Can't argue against the obvious possibility of Kodak and other labs having investigated the potential of pyrogallol and catechol developers in the light of works such as Levy's. Even the new lab researched developer products like those of Spur also seem to have avoided pyro.

[interneg]

Can't argue against the obvious possibility of Kodak and other labs having investigated the potential of pyrogallol and catechol developers in the light of works such as Levy's.

I think you're underestimating Marilyn Levy's influence - she chaired the SPSE's Processing Section at that time & was on the editorial boards of their journals - and was a very senior civil servant research scientist working for the US military - the self same institution whom Kodak also had deep ties with (& who effectively funded a great deal of basic science research at Kodak) - in other words, her peers at Kodak will have more than likely thoroughly investigated for themselves at the peer review stage. But you also have to remember that Levy was effectively working in specific applied fields rather than more basic research - which is where Kodak had much greater institutional depth - in other words, KRL was finding out about things like HQMS and its effects (and that AA can be used to achieve similar ends). The biggest problem is that people don't realise that most of the effects of 510-Pyro (for example) aren't coming from the pyrogallol, but from what could be achieved by building a suitable phenidone-ascorbate (or HQ or HQMS) relationship - the developer that is known to produce very intense adjacency effects is a later (1967) invention of Levy's (POTA - named after her workplace) - and those effects are from Phenidone alone (Kodak research seems to have been very aware of this soon after). Add a small amount of HQ, HQMS, AA (or probably just about any other source of semi-quinone) and the faults of POTA resolve themselves while leaving a potentially extremely high adjacency effect (from development inhibition effects) - and that same development inhibition effect modulates the Dmax at the same time (which is what seems to play a significant role in enabling POTA to deal with extreme brightness ranges). The bigger problem is that by cranking the definition up too high, your visual granularity also rapidly accelerates - and that is where balancing granularity against the various forms of sharpness enhancement have to be juggled to deliver adequately visually consistent results at 2x or 20x (to take an example), rather than visual granularity plotting like a rocket launch above 5x.


Even the new lab researched developer products like those of Spur also seem to have avoided pyro.

Spur (and Moersch) seem to be a strange combination of quite up-to-date science - modern sequestrants, HQMS, quite a bit of evidence of some understanding of electron pump (vs 'superadditive') developer designs & sometimes questionable choices of primary developing agent(s). There does seem to be a degree of awareness too about how the characteristics of phenidones (Dimezone-S in particular) can be exploited.

[Michael Kadillak]

Sulphite = not a staining developer. Levy's work was not driven by pictorial/ aesthetic requirement, but primarily by military/ scientific research need. And if Levy was looking at those recipes, Kodak will have looked at them too. Everyone was trying to improve on D-76 (and understand its mechanisms) for various reasons, but kept falling at the point they had to do double blind print comparison tests. Methods of dealing with AA's Fenton reaction issues were being intensely researched throughout this period - had DTPA or similarly powerful sequestrant been readily available at the time, AA would have come into use industrially in photochemistry in the 1960s/70s if not earlier. It's clear (from later documentation) that Kodak resolved the mechanism of Levy's POTA without disclosing it at the time - and used that knowledge (as did their competitors who were no slouches in the basic science) together with what they seem to have learnt about HQMS' effects (similar behaviour happens with AA, hence it being attractive as an HQ replacement) being preferential to all the other alternatives. A research result does not necessarily equal a viable/ reliable product - but it can count as prior art, and it's worth noting that Levy's earlier work with thickened monobaths was likely patented defensively against Polaroid (and potentially Kodak). And as for TEA, it was used in Dye Transfer at the time (and other processes etc) so it will definitely have been gone over rather thoroughly by Henn etc in getting to HC-110 (along with lots of other permutations that likely failed the desired parameters) - don't assume you are discovering anything new, and rather than desperately trying to dredge up post-facto defences of not-very-well-thought-out staining developers, you could take a few minutes to consider the nature of large scale photographic research at that time of that article - had there been enough evidence that under rigorous visual test conditions pyrogallol really had advantages over HQ or AA, there would have been concerted efforts to make use of it. Instead, Kodak were patenting ways to eliminate it from the process that relied on it - via the use of Dimezone-S and AA. Contemplate why that might have been.

Well since this rather bizarre dialog started with you pushing research versus actual realized print results as it relates to the utilization of pyro, I have been to the field three times and made 15 quality 8x10 negatives (made 6 negatives today that I will process tomorrow) all that will be processed with pyro that look simply marvelous. There comes a point in time where the legitimate objective of making high quality prints eventually supersedes this meaningless crap from the research department. This is a photographic forum, not a research forum. People post images they made with their cameras and could give a crap about a wide range of experiments that have no bearing on someone pursuing their visual craft. to the best of their ability. As a result I am tapping out.

[tundra]

Well since this rather bizarre dialog started with you pushing research versus actual realized print results as it relates to the utilization of pyro, I have been to the field three times and made 15 quality 8x10 negatives (made 6 negatives today that I will process tomorrow) all that will be processed with pyro that look simply marvelous. There comes a point in time where the legitimate objective of making high quality prints eventually supersedes this meaningless crap from the research department. This is a photographic forum, not a research forum. People post images they made with their cameras and could give a crap about a wide range of experiments that have no bearing on someone pursuing their visual craft. to the best of their ability. As a result I am tapping out.

What???? Your actual images don't listen to the theoretical woulda/coulda/shoulda analysis? The very idea.

For the record, I do see great value in sensiometry and photochemical research. Both were- and are important to maintain the craft. But the map and the territory ain't the same thing...