Fomabrom Variant III Emulsion Flaking

mshchem

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I use plenty of Foma paper, never seen this, or with any others. Probably a one in a million thing. Could be that Foma received a contaminated batch of paper??? It's fun to speculate, I would ask for a replacement and get back to work. Save the paper.
 

Nopo

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FWIW , When I first used VC foma paper, I had worse scaling problems than those seen in the image.
At first I thought it was a defective paper, but reading the foma instructions I decided to try a 1% kodak stop bath instead of the 2% as indicated by foma, I have not had any more flaking problems, which were worse than those described by you.
If this happened to me with VC, I think FB is more delicate.

PD. Because of the use of the translator I may have misused the English language, do not hesitate to ask for clarifications.
 

koraks

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Milpool said:
Just for fun (a long shot) I wonder if it would be worth trying regular tray processing just to rule out something this paper doesn’t like about the drum.
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This also came to mind, if only to just exclude it as a factor.

logan2z said:
I'm not sure what it wouldn't like about drum processing.
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Contrary to tray processing, you have to curve the paper inward in order to put it into the drum. This essentially stretches the paper base while compressing the emulsion, which results in shear forces between them. In itself, this should really not be a problem, but if this batch of paper was dodgy to begin with, it may be part of the reason why it's tipped over the edge, so to speak.
However, thinking about it, this would explain problems especially in the center of full sheets while small test strips would likely be less affected, or even not at all.

As to chemistry, I find it hard to imagine anything regularly used in paper developer to cause this. The difference between a 1% and a 2% stop bath really isn't that significant (whether it's citric or acetic acid). And virtually all developers are strongly caustic, so the paper is designed to withstand that. It's not like you're bathing it in something extremely aggressive like permanganate.
 

Marco B

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koraks said:
As to chemistry, I find it hard to imagine anything regularly used in paper developer to cause this. The difference between a 1% and a 2% stop bath really isn't that significant (whether it's citric or acetic acid).
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Maybe not the difference between 1 or 2% percent stop bath, but the difference between using acetic or citric acid as stop bath might be relevant.

At least this scientific article seems to indicate that acetic acid is used to extract gelatine from pig skin. This might be an indication that acetic acid may weaken the gelatine layer of the paper. Whether a similar effect also holds for citric acid IDK... but if the OP used acetic, he might instead try citric. Maybe the Foma paper is less suscepitble to damage in that:

The Effects of Acetic Acid Concentration and Extraction Temperature on Physical and Chemical Properties of Pigskin Gelatin

This research was aimed to study the influence of acetic acid concentration and extraction temperature on physical and chemical properties of pigskin …
www.sciencedirect.com
 

koraks

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Marco B said:
Maybe not the difference between 1 or 2% percent stop bath, but the difference between using acetic or citric acid as stop bath might be relevant.
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I severely doubt it. Gelatin is quite resilient to acidity; it does weaken at some point, but neither acetic nor citric acid will attack a hardened gelatin emulsion (all emulsions on commercial papers are hardened) to the extent that it'll start to flake off. Alkalinity is a different matter as this does indeed promote swelling, uncurling of the peptides and ultimately cause disintegration of the gelatin matrix. This is one reason why the emulsion is hardened - but even a non-hardened gelatin layer retains its integrity if soaked for 10 minutes or so in a carbonate bath (which I do routinely with self-made unhardened gelatin coatings, so I know it works).

Marco B said:
At least this scientific article seems to indicate that acetic acid is used to extract gelatine from pig skin.
Click to expand...
We're talking about a process that operates at high temperatures (>50C) and by definition acts on unhardened gelatin since this is the base material. The skins are soaked for 24 hours (!!!) in an acetic solution, then warmed up multiple times for warm extractions for 3 hours at a time. That's in no way representative of running a hardened photographic gelatin emulsion through a stop bath for a minute or so.
 

Marco B

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Totally agree, but there is of course also a huge difference between a nearly pure gelatine layer on paper directly exposed to the acid, and an industrial extraction process that needs to extract a small amount of gelatine from the matrix of stuff that constitutes a pig skin.

But I also totally agree this paper is likely a bad batch. I have had Ilford FB papers for > 24 hours in water without flaking...
 

koraks

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The difference is to the advantage of the former, really. As said, a photographic gelatin emulsion is generally quite robust especially with regards to the influence of acids. I've incorporated hydrochloric acid in unhardened gelatin layers (pig skin gelatin coincidentally) and it did just fine without any flaking etc. An emulsion like on this paper will be considerably more robust - even in its flaking form.

I really don't expect the stop bath to be the cause here; it's evidently some kind of problem with the product as such - either due to a manufacturing fault, or something related to storage conditions. Although regarding the latter, I'm struggling to see how this would happen with Foma's packaging, which is quite resistant to adverse conditions.

The way the emulsion flakes off makes me lean in the direction of something going very wrong with the adhesion of the gelatin emulsion to the underlying baryta layer. I'm insufficiently familiar with how the coating process works to say much about this, but the whole thing makes me wonder whether some kind of subbing or bonding layer between them fails under certain circumstances.
 

Marco B

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There is some other discussion regarding Foma papers and possible fragility here, with another person recommending a slightly more diluted stop at 1% acetic max:

In Praise Of Fomabrom Variant III 111 VC FB

I have been silver printing for upwards of 5 decades on- and off, so I've seen papers from Velox, to Kodabromide, to Polycontrast, to Zone VI graded, to ... well, modern times. I just wanted to put in a plug for the aforementioned Formabrom. The stuff is just ... well, gorgeous. It has a...
www.photrio.com
 

koraks

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If a change of 2% to 1% acetic (or citric) acid is going to make a difference, it's clear that you're balancing on a very fine edge and the real underlying problem is with the paper itself. Again, it's not normal for Fomabrom to be this sensitive to frilling, let alone gross delamination, regardless of how you process it. I've printed a lot on this paper; for me it has always worked trouble-free.
 

Milpool

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That difference in concentration would not be meaningful in this context. In any case Foma's own processing instructions for this paper indicate the use of a standard 2% acetic acid (or citric acid) stop bath.
 
OP
OP

logan2z

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Quick follow-up:

I got a response from Freestyle and they're going to replace the paper with a new box. I'll give it a shot when I receive it and hopefully have better luck this time.

Thanks to everyone for weighing in with their thoughts.
 

GregY

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logan2z said:
Quick follow-up:

I got a response from Freestyle and they're going to replace the paper with a new box. I'll give it a shot when I receive it and hopefully have better luck this time.

Thanks to everyone for weighing in with their thoughts.
Click to expand...

Excellent! Let us know how your next foray w Foma goes!
 
OP
OP

logan2z

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The replacement paper from Freestyle just arrived. Kudos to them for getting the replacement out to me so quickly. I'm going to give it a try over the weekend and I'll report back.
 
OP
OP

logan2z

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Sal Santamaura said:
More than six weeks later, how'd the replacement paper fare?
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I wish I could tell you. I recently fractured my foot and haven't been able to spend any time in the darkroom. Hoping to finally be able to spend some time this weekend making prints. I'll post a follow-up ASAP.
 
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