Best B&W Film Reversal Kit: Foma, Adox Scala, or Bellini

[miha]

@Henning Serger these are stunning! How was this film developed?

 

[miha]

@Ivo Stunga thanks, the spectral sensitivity of up to 750 nm helps achieve this look, I think.

 

[Henning Serger]

@Henning Serger these are stunning! How was this film developed?

SCALA process. As written in my posting above, I am developing both ADOX SCALA 160 and 50 in the SCALA process, because this process is optimised for these films.

 

[miha]

SCALA process. As written in my posting above, I am developing both ADOX SCALA 160 and 50 in the SCALA process, because this process is optimised for these films.

Thank you. Sorry for being pedantic but I assume you mean the ADOX Kit. The (AGFA) SCALA process, as we know it from the past, was something different.

 

[Film-Niko]

Hello all,

I'm currently evaluating different black and white reversal kits and would appreciate any insights or recommendations. The three kits I'm considering are Foma, Adox Scala, and Bellini. Here’s what I’ve gathered so far:

- Bellini includes dichromate, which eliminates the need for re-exposure.
- Adox Scala is marketed as the most eco-friendly option, combining some of the baths.
- Foma has been available for the longest time and has a good reputation.

My goal is to project the slides, not scan them. I’m interested in hearing about user experiences, including which films you used with these kits and how the results compared.

Thank you.

Scala 50 film developed in the Scala reversal process. That is what I am doing since the introduction of the Scala reversal kit.
Results are really excellent.
I can completely confirm from my experience what the other members have reported about this combination.

 

[Film-Niko]

Thank you. Sorry for being pedantic but I assume you mean the ADOX Kit. The (AGFA) SCALA process, as we know it from the past, was something different.

The Adox Kit has the official name ADOX SCALA reversal kit: https://www.adox.de/Photo/adox-scala-reversal-kit/
Adox owns the brand name for SCALA for the BW reversal process.

 

[miha]

Can someone share a photo of the Kodak Gray Card Plus taken with an ADOX HR-50 film

 

[Lachlan Young]

20II is on my list of films to try out

It was somewhat eccentric in the Agfa Scala process - contrast gradient was more or less controlled (at least in flatter light), but you could very much see that the toe and shoulder remained angles rather than curves - if that makes sense.

Probably going to try an roll in Adox Scala and see what that does (once I can find the FD time I swear I saw somewhere). Any FD that uses a silver solvent is probably not a good idea - gelatin swelling development accelerators seem to be fine though.

 

[Ivo Stunga]

Why exactly and what would you use instead?

 

[Lachlan Young]

Why exactly and what would you use instead?

Silver solvents effectively produce development inhibition effects via their actions on the emulsion, which seems to be more of a problem the thinner and more chemically accessible the emulsion is (CMS is extremely monodisperse and apparently very sensitive to silver solvents) - thus there's a time restriction (about 5-6 mins from recall) for a solvent developer to achieve access to and development of all the silver before the solvency kicks in. Thus there seems to have been a shift in interest to development accelerators.

The polyglycol that crops up in the patent literature for B&W reversal is usually Polyethylene Glycol of a specific molecular weight - you will need to experiment. Scala seemed to use PEG-1500 in the patent disclosed process, I recall that the Kodak Tmax reversal kit also disclosed PEG in one MSDS. A different MW was also found to seemingly aid in making several current papers lith pretty well.

The other oddity seems to be that MQ may have specific benefits over PQ in BW reversal FD - not discussed in the relevant patents, but good data can be found elsewhere that shows that MQ has no development inhibition effects (as opposed to exhaustion effects of dilute Metol), while PQ has a sliding scale of them (and they're desirable for BW neg working materials to improve adjacency effects) - which may cause problems in thin, extremely accessible BW emulsions but not in much thicker (3-4x) E-6 emulsions.

As a side note, it's also highly likely that the difference between Fuji Neopan 400 and 1600 was the incorporation of a development accelerator within the emulsion

 

[Ivo Stunga]

Thanks! A wealth of information to get around, nice!
So instead of X amount of hypo I could add X amount of X molecular weight PEG to my first dev and have it perform more actively/"kosher"?

What would those quantities be approximately when making 500ml developer?

 

[Lachlan Young]

Thanks! A wealth of information to get around, nice!
So instead of X amount of hypo I could add X amount of X molecular weight PEG to my first dev and have it perform more actively/"kosher"?

What would those quantities be approximately when making 500ml developer?

Development accelerators that swell the emulsion and silver solvents do roughly the same thing - they enable the developer to get the desired level of emulsion access - so one isn't necessarily more or less Kosher, just that modern emulsion technology is often designed to interact in particular ways with solvency (good for neg/ pos processes) - but that causes problems for reversal, thus you can see why development accelerators become of interest.

The Agfa patent in question suggests they used 1.5g/l of PEG-1500 in the 1990s Scala process (it's pretty clearly a defensive patent around trying to cross-pollinate E-6 tech into the process - and demonstrates possible partial solutions to getting around what are clearly development inhibition issues there). There's some very interesting aspects to the choices of components in the FD (including what looks like in-situ formation of sodium sulphate to control swell?) - I think it does give some useful insight into where BW reversal research travelled to, when high aspect ratio grain structures appeared in the industry.

 

[Ivo Stunga]

Sweet - way above my understanding, but interesting nonetheless!

Using hypo and those 5 minutes - meaning that solvent has little to no chance to dissolve anything with development times under 5 minutes? Shortest I got was pulling HR-50 one stop, 7min dev time - so just ~2 minutes of solvent activity?

 

[miha]

Can someone share a photo of the Kodak Gray Card Plus taken with an ADOX HR-50 film

Well, I found it online - left Adox HR-50, right Kodak Tri-X :

Link: (The Naked Photographer)

 

[ChrisGalway]

View attachment 379012

Portraits of Ukrainian artist Dasha.
In real life under the loupe and in projection the quality is of course in a different league compared to these phone snapshots.
But I think they give you at least a certain impression what the film is capable of.

Best regards,
Henning

Wow Henning, superb! What a pity that Scala film is not available in 120. Have you tried any 120 film that you could recommend?

 

[Alessandro Serrao]

Silver solvents effectively produce development inhibition effects via their actions on the emulsion,

From Grant Haist, II volume:

"The nature of the silver image formed on reversal development is explained
on the basis that both chemical and physical development are
occurring in the first developer. The thiocyanate dissolves some of the silver
from the silver halide crystals and, in the presence of large amounts of sodium
sulfite, releases the silver ions for reaction with the sulfite ions. The thiocyanate
is available again for dissolving more silver halide. The silver sulfite
and some silver thiocyanate, as well, are unstable in the presence of freshly
developed silver filaments of the chemically formed photographic image.
The silver from the complexes is deposited upon these silver filaments,
thickening the filaments slightly but not materially increasing their lightstopping
power (covering power). The deposition is accelerated by the
presence of the silver particles of the image, and the most silver filaments
occur in the high densities of the image formed in the first developer. Thus,
unexposed or undevelopable silver halide crystals in this area are dissolved
away, leaving almost no silver halide for subsequent development to form
the positive image. In this way a combination of chemical and physical
development in the first developer achieves a desired fogfree result that
cannot be obtained by exposl.!re alone.
The action of silver halide solvents upon the image obtained by reversal
processing has been studied by E. Klein, 3
• -
32 who used the electron microscope
to observe the thickening of the filamentary silver in the thiocyanatecontaining
first developer. Klein concluded: "Physical development on
chemically developed silver takes place most readily if on the one hand
the largest possible surface of undeveloped silver halide is available for complex
formation, and on the other hand a large surface of developed silver
is available for the deposition of physically developed silver. This will probably
occur in the middle range of the characteristic curve. A relatively large
quantity of silver is here physically deposited without any contribution to
the covering power. This silver can subsequently not be used for the chemical
development of the reversal density." At the lower exposures there were
only a few exposed silver halide crystals and very many unexposed crystals.
Physical development was slowed because of the lack of the metallic silver
The Steps in Re11ersal Processing of Black-and-White Materials 323
of the image that is needed to accelerate the solubilization of the unexposed
silver halide. Much of the silver halide is unchanged. This silver halide is
chemically developed to form the positive image. This metallic silver has
great light-stopping action. The maximum density thus has lower silver
than the minimum density, which has high silver and lower density where
physical development had occurred.
The chemical development, being a fast process, provides the centers for
silver deposition by physical development, the slower process. Near the
surface of the emulsion layer, silver ions that have been solubilized pass
into the solution of the developer. This solubilized silver is quickly deposited
on the chemically developed silver filaments, leading to the accelerated solution
of silver halide grains near the surface in the vicinity of the silver particles.
Deeper in the emulsion layer this condition does not occur, as the
physical development rate is slowed because silver ions soon saturate the
space between silver halide crystals.
The difference in the rates of physical development at different levels in
the emulsion layer has been reported to decrease the width of a line image
nearer the surface. Retardation of the physical development in the top part
of the emulsion layer was said 33 to result when 2-mercapto-5-sulfobenzimidazole
was added to the first developer. The change in image detail dimensions
was decreased and the sharpness of the image edges was increased when the
film was treated with the developer containing the 2-mercapto-5-sulfobenzimidazole."

I don't get how a silver halide solvent could produce development inhibition...

 

[Alessandro Serrao]

Development accelerators that swell the emulsion and silver solvents do roughly the same thing - they enable the developer to get the desired level of emulsion access

Again no, reading what Grant Haist has written.

 

[Lachlan Young]

Again no, reading what Grant Haist has written.

Haist's book was heavily censored for publication. That is well known.

In many cases what he writes was correct for emulsions of 10-15 years earlier. It's an overview of what Kodak was OK with disclosing, not a summary of the state of the art - the half-life of knowledge within photographic science was shrinking pretty rapidly from 1955-80. Exploitation of solvency derived development byproducts to enhance adjacency effects was very commercially sensitive then. If you read Haist without cross-reference to newer patents, academic texts and theses while proclaiming him to be the sole basis of knowledge, that's fundamentally flawed.

He is not wrong for thicker single layer emulsions that have relatively more buried iodide (the older Agfa patent (for what looks like the Dia Direct process) that is cited in the Scala patent effectively follows exactly what Haist states), but more modern ones (be they thin single layer with epitaxy or tightly packed multiple thin layer) that are designed to interact strongly and rapidly with developer solvency to release development inhibiting agents are obviously going to cause problems. Your pull quote does however give some clear hints as to why Agfa chose the specific sequestrants in the Scala FD (silver complexing). You should always start from the perspective that the Agfa engineers were not inferior to the Kodak ones, and then try to discern why they chose particular formulations, rather than demanding fealty to Haist's publication without any understanding of the context it was produced in.

 

[Alessandro Serrao]

Haist's book was heavily censored for publication. That is well known.

In many cases what he writes was correct for emulsions of 10-15 years earlier. It's an overview of what Kodak was OK with disclosing, not a summary of the state of the art - the half-life of knowledge within photographic science was shrinking pretty rapidly from 1955-80. Exploitation of solvency derived development byproducts to enhance adjacency effects was very commercially sensitive then. If you read Haist without cross-reference to newer patents, academic texts and theses while proclaiming him to be the sole basis of knowledge, that's fundamentally flawed.

He is not wrong for emulsions that have relatively more buried iodide, but more modern ones that are designed to interact strongly and rapidly with developer solvency to release development inhibiting agents are obviously going to cause problems. Your pull quote does however give some clear hints as to why Agfa chose the specific sequestrants in the Scala FD.

Sorry, I've presented an academic text with references.
Can you point any references corroborating what you're stating?
I know the use of PEG-400 in the first developer and hexametaphosphate in the bleach but haven't found any academic, theses and newer patents...

 

[Lachlan Young]

Sorry, I've presented an academic text with references.
Can you point any references corroborating what you're stating?
I know the use of PEG-400 in the first developer and hexametaphosphate in the bleach but haven't found any academic, theses and newer patents...

Once you know who the relevant researchers were at Kodak, Ilford etc, you can look up the relevant stuff very fast. There's plenty academic/ patent material about development inhibition/ acceleration, control layers and all that. It would end up a very, very boringly long post to list everything relevant. Suffice to say, you might want to look into those involved in Delta technology at Ilford, and some of those who were supervised by Gilman and Willis at Kodak. That'll tell you much more about what Haist chose to/ had to omit or only hint at in broad terms.

The critical context you need to understand is that some of the major emulsion design improvements for neg-pos are not beneficial to reversal, and that Agfa's engineers had to work round that (Scala was clearly done as cheaply as possible with very few unique formulations - hence the patent in the first place).

 

[Alessandro Serrao]

The critical context you need to understand is that some of the major emulsion design improvements for neg-pos are not beneficial to reversal

Apart from all the technicalities of various first developer compositions, if a film subbing layer isn't designed to withstand a permanganic acid bleach there's no point imho to continue to use that particular film. And there's no point to mess around with bleach composition.
Which it boils down to use films specifically designed to be reversed, such as Fomapan R 100.
At this point I think it's better also to use a tailor-made reversal kit than fiddling around with many possible combinations of chemicals. Cheaper in the long run (you don't have to make many trials), faster and with securer results.
That is: Foma reversal kit for Fomapan R 100 (and maybe Fomapan 100) and Adox reversal kit for Scala 50.
It's more than sufficient as I see it. In other words: I wound't waste my precious eFKe films (or any other not-produced-anymore films) to try to reverse them, although I know they will reverse very well...
Then you could start to try to replace the second developer to see the difference, being the second development a non-critical step. For example in the Foma reversal kit (which is doing a great job even if it is 4 years outdated) I tried to replace the second developer with the Bellini Hydrofen I have (which is also heavily outdated). Well, to much of my surprise the slides turned out richer and "blacker", with higher DMax that reusing the first developer as the second one.
Then a final selenium toning step can be implemented to gain even more Dmax.

 

[loccdor]

Does anyone know if you can reuse the Adox Scala Reversal kit to get more than their advertised capacity, as is the case with C-41 and E-6 kits? I want to try it but I'd like to get at least 15 rolls (5 separate developments in a 1000ml tank) from a kit of that price.

 

[Ivo Stunga]

Apart from all the technicalities of various first developer compositions, if a film subbing layer isn't designed to withstand a permanganic acid bleach there's no point imho to continue to use that particular film. And there's no point to mess around with bleach composition.
Which it boils down to use films specifically designed to be reversed, such as Fomapan R 100.

I don't know why, but R100 gives constantly poor results with Ilford Reversal - soft, poor resolving power, mushy - no fun at all to project. Meanwhile Delta 100, FP4+, Kentmere 100, HR/Scala 50, Aviphot 80 and 200 repackagings, Ferrania P30 and so on... are just marvelous, all in dilute permanganate bleach.
The softness is on par with Kodak E100D and I'm puzzled - are these films inherently poorer performing or is something suboptimal in R100+PQ and my local lab + E100...

Does anyone know if you can reuse the Adox Scala Reversal kit to get more than their advertised capacity

This would much more likely turn me into a customer indeed. Currently this is unreachable to me as my costs with Ilford are a tad under 1€ per film, but Adox kit would rise that 7 times and be over in just two months at my shooting rate, and to ship this again and again - shipping costs alone would quickly amount to a burden too heavy.

 

[Alessandro Serrao]

Does anyone know if you can reuse the Adox Scala Reversal kit to get more than their advertised capacity, as is the case with C-41 and E-6 kits? I want to try it but I'd like to get at least 15 rolls (5 separate developments in a 1000ml tank) from a kit of that price.

I think it's not possible and it's also stated in their instructions. Maximum capacity is 8 rolls.

 

[Alessandro Serrao]

I don't know why, but R100 gives constantly poor results with Ilford Reversal - soft, poor resolving power, mushy - no fun at all to project. Meanwhile Delta 100, FP4+, Kentmere 100, HR/Scala 50, Aviphot 80 and 200 repackagings, Ferrania P30 and so on... are just marvelous, all in dilute permanganate bleach.


This would much more likely turn me into a customer indeed. Currently this is unreachable to me as my costs with Ilford are a tad under 1€ per film, but Adox kit would rise that 7 times and be over in just two months at my shooting rate, and to ship this again and again - shipping costs alone would quickly amount to a burden too heavy.

All correct considerations. I always thought that sharpness could be related to how much the gelatine swells. If the gelatine swells much the sharpness will be low. Maybe I'm completely wrong on this.
As for the kit vs. raw chemicals, Ivo consideration is very correct. I wish I could replicate what he has done, he has mastered this art via trials and errors. It's a daunting task and since I'm lazy I cannot think I'm up to. Hence my consideration to use only reversal kits.