Wanting to try reversal processing but also not die

Lachlan Young · Apr 13, 2020

Eldorado Quibbo said:
I tend to trust more what Grant & Haist say about not all Ag being developed. I've reported the extract, above. I think it's correct what they say about it.

Grant Haist is more likely to be correct on this than any random internet claims - and it's worth noting that one of the peer reviewers was Ron Mowrey (Photo Engineer). As I understand it, there were omissions related to commercial sensitivities, especially in terms of film technology that was in R&D at the time, but overall it gives a good overview of fundamental emulsion & chemical behaviour. It is now possible to more effectively sensitise & 'use' the silver, but not in the way that '138s' proposes. Instead in negative films it allows either a lower quantity of silver/ m2 to be used or a higher effective speed for the same amount of silver because it can be better sensitised and used.

138S said:
Sorry, I've not explained it clearly. What you say is true with classic home reversal, this is a calibration I made with a hacked Rodinal and Sn fogging 2nd developer :

View attachment 243842

We see there the same gradient not matering development time, we have some DMax improvement with extended 1st developer time. The top 6 min curve was using a different solvent...

It is a calibration I made personally, so I'm well aware of that.

What I was trying to propose is a reversal variant with minimal silver solvent effect, with enhanced energy, with partial light re-exposure, and with promoted infectious development of the unused silver, to reach (say) 4.0DMax with Delta 100, while having clear highlights. In that case, with little silver solvent effect, 1st development gradient controls the slide contrast.

My suposition is that a silver solvent rich first developer limits actual development, as unexposed little silver crystals around big exposed crystals are disolved by when infectious development would attack them, so no density-contrast increase would take place after that point.

A more energic developer would develop more before touching unexposed crystals are destroyed by the solvent... so what you say is true for regular BW reversal.

...but consider that I was talking about another situation: no silver solvent, when this limitation if not acting then 1st development time rules on contrast, which follows Mr. Woods recommendation, and he is the one offering 4.4D from Delta 100

Disclose the developer formulations you are using for first developer, second developer and reversal bath. Otherwise your 'data' is just random numbers. It currently sounds like you are desperately trying to contravene the inherent reversal behaviour of the film in a mistaken belief you can make it behave as you arbitrarily wish.

138S · Apr 13, 2020

Lachlan Young said:
It currently sounds like you are desperately trying to contravene the inherent reversal behaviour of the film in a mistaken belief you can make it behave as you arbitrarily wish.

Lachlan, let me smile Excuse me, but I've laughed a lot at your wording.

Let me explain you that's the counter, I make calibrations to learn how film behaves. Beyond the too low contrast we were correcting, do you see anything abnormal in those curves ?

Lachlan Young · Apr 13, 2020

138S said:
Lachlan, let me smile Excuse me, but I've laughed a lot at your wording.

Let me explain you that's the counter, I make calibrations to learn how film behaves. Beyond the too low contrast we were correcting, do you see anything abnormal in those curves ?

There's no point in even looking at them until you disclose the EI you used, metering method, first developer (and composition as far as known), type of reversal used, second developer (and composition as far as known). Only after all of those have been disclosed is there any point whatsoever in discussing the results. If you continue to refuse to explain your process composition, the only conclusion that could be drawn is that you now know there are glaring errors of technique on your part that would be immediately obvious.

138S · Apr 13, 2020

Lachlan Young said:
There's no point in even looking at them until you disclose the EI you used, metering method, first developer (and composition as far as known), type of reversal used, second developer (and composition as far as known). Only after all of those have been disclosed is there any point whatsoever in discussing the results. If you continue to refuse to explain your process composition, the only conclusion that could be drawn is that you now know there are glaring errors of technique on your part that would be immediately obvious.

Lachlan, there is no EI, and no "metering method": this is from contact copies of an Stouffer T2115 wedge on film strips, with luxmeter measured real Lux reaching the wedge, so having absolute H units (Log Lux·Second) in the exposure axis, like in Kodak/Fuji datasheets. If you need to review how film is calibrated then see BTZS book, it is a good reading for that.

When calibrating with absolute exposure units we can predict exactly what density we'll obtain for any spot in the scene, when wanting to know it. And of course we know what ISO speed and metring says.

Usually I adjust contrast to match Provia, and as Provia datasheet also has absolute units I simply adjust my BW slides EI to match the Provia result after comparing the exposures at the respective speed points. In that way I adjust the reversal processing and EI from sensitometric curves nailing a perfect result since the very first roll. Of course I may later adjust EI/processing for aesthetics, but from the Reversal calibration and Provia reference I get very good results at the first try.

I've not been shooting BW slides for two years, I'm to engage again soon, this time I've my calibration software ready and newly learned concepts to try to enhance my workflow, when I have it I'll publish may results if they are worth.

Lachlan Young · Apr 13, 2020

138S said:
Lachlan, there is no EI, and no "metering method": this is from contact copies of an Stouffer T2115 wedge on film strips, with luxmeter measured real Lux reaching the wedge, so having absolute H units (Log Lux·Second) in the exposure axis, like in Kodak/Fuji datasheets. See BTZS book, it is a good reading for that.

Well yes, you should be using a step wedge, but why are you so unwilling to tell us any of the rest of your process? Let alone whether you used 135, 120 or sheet film forms of HP5+?

138S · Apr 13, 2020

Lachlan Young said:
Well yes, you should be using a step wedge, but why are you so unwilling to tell us any of the rest of your process? Let alone whether you used 135, 120 or sheet film forms of HP5+?

I made that particular calibration for a friend who is a proficient Pro chemist, in my darkroom with him. I don't recall his exact formula, If you are very interested I can search it in my darkroom or ask him, with HP5+ he was using Rodinal R09 with boosted pH and silver solvent. 2nd developer was the same without silver solvent with Sn fogging, but 2nd development was made also lights open to completion as we saw all halide disapear totally.

That day, just the contact strip falling in the 2nd dev...

He had low contrast and poor DMin, so I helped him troubleshooting those two factors.

That time I learned what Eldorado explained (https://www.photrio.com/forum/threa...g-but-also-not-die.174178/page-7#post-2269433), with the regular processing 1st development you cannot adjust contrast from development time because of the silver solvent (I guess) destroying small crystrals.

With my chemist friend we had an smart idea: not using silver solvent in the 1st development... Then if wanting to clear highlights we use the silver solvent in an additional bath just after a water stop bath or (better) after clearing bath, in that way we can separately adjust contrast in the 1st development and DMin in a following "silver solvent" bath, with a less complex interaction. As silver solvent and 1st development have an interaction an smart way is separating both jobs in two separated baths.

...but presently I'll experiment wtih no solvent (or the less possible), to me it's the way to obtain an extended DR in the slide.

Lachlan Young · Apr 13, 2020

138S said:
I made that particular calibration for a friend who is a proficient Pro chemist, in my darkroom with him. I don't recall his exact formula, If you are very interested I can search it in my darkroom or ask him, with HP5+ he was using Rodinal R09 with boosted pH and silver solvent. 2nd developer was the same without silver solvent with Sn fogging, but 2nd development was made also lights open to completion as we saw all halide disapear totally.
...
With my chemist friend we had an smart idea: not using silver solvent in the 1st development... Then if wanting to clear highlights we use the silver solvent in an additional bath just after a water stop bath or (better) after clearing bath, in that way we can separately adjust contrast in the 1st development and DMin in a following "silver solvent" bath, with a less complex interaction. As silver solvent and 1st development have an interaction an smart way is separating both jobs in two separated baths.

...but presently I'll experiment wtih no solvent (or the less possible), to me it's the way to obtain an extended DR in the slide.

I think the problem is caused by the silver solvent and lack of superadditivity. The silver solvent adds fog, which will reduce Dmax & you should be well aware that the lack of superadditivity isn't helping either. I went for a look for the MSDS of the TMax reversal kit & it turned out that the first developer had... PEG in it. Just like Agfa. So, it's reasonable to conclude that while a first developer for E-6 is fine being foggy (and indeed potentially helps with sharpness), the first developer for BW reversal today is likely best if low solvency, strongly super-additive & using a development accelerator in the form of a specific molecular weight of PEG to ensure the silver is fully accessed & developed.

The next problem is that while you might have made an effective reversal bath (p-aminophenol is used as a preservative of SnCl2 in E-6), it is probably not much use as a second developer. You're going to need something much stronger - a paper/ universal dev sort of deal. I'd stick to light reversal (again recommended in E-6 documentation as a reversal bath troubleshooting method) until you get your first and second developers running well.

Do make sure you read the TMax reversal kit documentation thoroughly - it contains some key details which suggest why DR5 likely uses 2 bleach baths.

Eldorado Quibbo · Apr 13, 2020

138S said:
With my chemist friend we had an smart idea: not using silver solvent in the 1st development... Then if wanting to clear highlights we use the silver solvent in an additional bath just after a water stop bath or (better) after clearing bath, in that way we can separately adjust contrast in the 1st development and DMin in a following "silver solvent" bath, with a less complex interaction. As silver solvent and 1st development have an interaction an smart way is separating both jobs in two separated baths.

This is an old idea. It's in the book by Oscar F. Ghedina, Il fotoricettario.
https://www.nadir.it/test/DIA_BN/default.htm
Of course this is a less than average method of inversion, since the hypo in a separate clearing step will eat away also densities (DMax)...

Eldorado Quibbo · Apr 13, 2020

Lachlan Young said:
I went for a look for the MSDS of the TMax reversal kit & it turned out that the first developer had... PEG in it.

Are you sure?
I remember that Kodak uses DTOD as a silver halide solvent in the first developer...

Lachlan Young · Apr 13, 2020

Eldorado Quibbo said:
Are you sure?
I remember that Kodak uses DTOD as a silver halide solvent in the first developer...

In the cinema reversal process, DTOD is used, in the TMax kit PEG is used.

Eldorado Quibbo · Apr 13, 2020

Lachlan Young said:
In the cinema reversal process, DTOD is used, in the TMax kit PEG is used.

So it seems PEG 400 is the way to go, much cheaper than DTOD.

Lachlan Young · Apr 13, 2020

Eldorado Quibbo said:
So it seems PEG 400 is the way to go, much cheaper than DTOD.

Maybe - the Agfa MQ developer in the patent used PEG 1500, the HQMS variants used a lower molecular weight one. I imagine that it'll likely have quite a lot to do with the ability of the developer to penetrate the emulsion evenly - something that HQMS is quite specifically chosen for.

Eldorado Quibbo · Apr 13, 2020

Lachlan Young said:
Maybe - the Agfa MQ developer in the patent used PEG 1500, the HQMS variants used a lower molecular weight one. I imagine that it'll likely have quite a lot to do with the ability of the developer to penetrate the emulsion evenly - something that HQMS is quite specifically chosen for.

It would be interesting to know if PEG also works with common paper developer, such as Ilford PQ Universal...
Or use directly Kodak Polymax T paper developer, which contains Diethylene glycol.
https://www.freestylephoto.biz/static/pdf/msds/kodak/SDS_US_English_-_Polymax_T_Developer.pdf

Lachlan Young · Apr 13, 2020

Eldorado Quibbo said:
It would be interesting to know if PEG also works with common paper developer, such as Ilford PQ Universal...
Or use directly Kodak Polymax T paper developer, which contains Diethylene glycol.
https://www.freestylephoto.biz/static/pdf/msds/kodak/SDS_US_English_-_Polymax_T_Developer.pdf

I think it needs to be a polyglycol - but, yes, I reckon the first test I'd want to carry out would be with PQU - I suspect there might still be some speed loss (I recall high definition developers have very little speed loss, & possibly even a little gain, which may be why Agfa went with MQ for their first dev).

138S · Apr 13, 2020

Eldorado Quibbo said:
This is an old idea. It's in the book by Oscar F. Ghedina, Il fotoricettario.
https://www.nadir.it/test/DIA_BN/default.htm
Of course this is a less than average method of inversion, since the hypo in a separate clearing step will eat away also densities (DMax)...

Not less than the average, just the average.

Because of that I plan to mostly supress solvent, or at least the most I can. It will be interersting to find the effect of PEG, but also playing with energy and toning.

thuggins · Apr 13, 2020

12% H2O2 is readily available on Anazom. It shows the normal shipping. 30-35% looks like it is available commercially under various labeling.

Raghu Kuvempunagar · Apr 14, 2020

138S said:
with HP5+ he was using Rodinal R09 with boosted pH and silver solvent.

Did you/your friend try out any of the well known first developers (such as those posted by @Ian Grant ) before settling down with the Rodinal hack developer?

138S · Apr 14, 2020

Raghu Kuvempunagar said:
Did you/your friend try out any of the well known first developers (such as those posted by @Ian Grant ) before settling down with the Rodinal hack developer?

He tested many reversal formulas... but chemists a bit are like witches, they want to cook the soup they eat

A fraction of his photo-chem shelves:

Some 60 stored substances for reversal...

Raghu Kuvempunagar · Apr 14, 2020

138S said:
He tested many reversal formulas...

And he got low contrast as well as low DMax for HP5+?

138S said:
A fraction of his photo-chem shelves:

You really don't want show-your-chem-shelf-porn posts to derail this thread. It could be a good idea for a separate thread though.

138S · Apr 14, 2020

Raghu Kuvempunagar said:
You really don't want show-your-chem-shelf-porn posts to derail this thread. It could be a good idea for a separate thread though.

You asked about what my friend knows or not, that chem-shelf-porn doesn't say all, many (like me) have decorated shelves, but another thing is writing all reactions , calculating equilibriums and speed of the reactions. Still photo-chemistry is quite complex and there is a lot of conceptual knowledge around.

Raghu Kuvempunagar said:
And he got low contrast as well as low DMax for HP5+?

This was only a first try of a new recipe... both issues were solved. But that experiment was part of a more ambitious challenge that's still in course. The idea is using two separated 1st developers with different goals, with a water rinse in the middle. None of those developers contain solvent, which is applied as necessary in a separated bath, anyway the goal is to need a way lower solvent action.

Nothing wrong in testing... this may not end in a better processing, but sure it will be a good teaching at least.

Raghu Kuvempunagar · Apr 14, 2020

138S said:
both issues were solved.

What's the DMax and gamma you got for HP5+ after solving the issues? And what did the well-known first developers give in comparison?

138S · Apr 14, 2020

Raghu Kuvempunagar said:
What's the DMax and gamma you got for HP5+ after solving the issues? And what did the well-known first developers give in comparison?

In that particular test, IIRC we adjusted gamma in the linear section to match Reversal TX (https://www.kodak.com/content/products-brochures/Film/TRI-X-Reversal-Film-7266-Technical-Data.pdf) specs at -2 (negative value). DMin ended in 0.25 and DMax in 3.0, IIRC

As we ended in a separated solvent bath, we adjusted contrast at a glance. We found 2nd development may be further enhanced by not developing to "total" completion and by promoting low fog, following fixer action to remove the halide that was to deliver fog, but this improvement is still in course.

When we limit fog then we also lower DMax anyway... what counts is the range, when having the range then adjusting DMin is not much a concern. My view is that infectious development is a key concept to extend range.

Raghu Kuvempunagar said:
And what did the well-known first developers give in comparison?

At this point still I cannot speak about actual advantages, I can speak about control.

Presently, my view is that separated solvent bath is what allows to easily adjust processing, probably a regular processing recipe optimized for a film is easier for many, but separated solvent allows better control.

My goal is understanding well the impact of restrainer and energy in the results, being the developer agent a less important factor, what is important is how we use that agent (restrainer, pH...).

IMO that german Lab and DR5 are one or two steps beyond what popular BW reversal is able, and I want to learn why.

Lachlan Young · Apr 14, 2020

138S said:
IMO that german Lab and DR5 are one or two steps beyond what popular BW reversal is able, and I want to learn why.

Well, follow up on what Agfa and Kodak's mid-90's processes were. Note the correlations and why. Kodak's cine reversal bleach bath is essentially the same as the one recommended in the Agfa patent upthread - aka a chelation agent added to acidified permanganate. If two different research teams of considerable ability came to the same conclusion for processes intended for industrial use, follow what they did. Note that in both first developers intended for still use - ie the Kodak TMax kit & the Agfa Scala process, both first developers seem to use no extra solvency, but instead use PEG as an accelerator - and possibly some degree of in-situ HQMS formation. D-94A using DTOD is slightly different, it's meant for roller transport use & a 90s developing time - rather different from the ~6 mins aim in Scala - D-94A is also significantly more alkaline than the aim for the first developer in the Agfa patent. The Scala process dates from about 1995, superseding whatever process the ISO 32 Dia-Direct used. It seems likely that there was a discovery that higher solvency developers can have sharpness benefits in BW negative (and colour positive films), but that an development accelerator was more effective in getting full speed, clean highlights and excellent Dmax in BW transparencies. So in other words, your research should start from here: no solvency in either developer; use a polyglycol as a development accelerator; both developers need to be strong and super-additive, with the first developer potentially aiming to form or use HQMS - and as high definition as possible; chemical reversal ignored until both developers perform consistently; bleach bath as per Kodak and Agfa recommendations; ignore the 'cookbooks' and what 'worked' with old relatively uncontrolled emulsions of 70 years ago.

pentaxuser · Apr 14, 2020

I wonder if we ever answered EASmithV's questions* ( who? you say ) Can't be many threads where any OP has not responded at least once in 198 posts since his opening post

pentaxuser

Raghu Kuvempunagar · Apr 14, 2020

Lachlan Young said:
it'll likely have quite a lot to do with the ability of the developer to penetrate the emulsion evenly - something that HQMS is quite specifically chosen for.

Interestingly, Polyethylene Glycol is used by some in Pyrocat developers. I wonder if that made any difference to the activity of Pyrocat developers. Or is it only HQMS that benefits by the use of PEG?

Wanting to try reversal processing but also not die

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