What are those white dots on my negatives?

Dear all,

It has been a few years now that I am in some sort of "technical rut" when it comes to film developing. Since I moved in our latest home, I keep on finding ways to mess up my negative development, flaws that ruin pictures that are important to me - and on which I spent a good amount of time and energy. I have a scientific background and usually manages to isolate the variable that is the cause of the problem but I am stumped with this last flaw and asking for help identifying the cause of the problem.
I have been trying to go through a pile of 120 film that I have shot over the past years. The rolls are stored in a closet, at room temperature - I live in Louisiana but the AC prevents the temperature and humidity to be too bad inside.

The issue:
The flawed negatives show a various amount of white spots. Some pictures are manageable in Photoshop, some are ruined. The white spots are of various sizes and have a darker "aureola".

The context:
The rolls have been shot around 2 years ago, just before we had our son (which explains the delay in processing). The rolls that show issues are Ilford fp4+ from different batches bought at different times.
At first I thought my developer had gone bad. I had used Pyrocat HD in Glycol and thought maybe some of it had crystallized (even though the developper is recent). I then used XTOL but found the same spots.
I use filtrated water from a PUR system, that attaches on the faucet.

I have attached 100% details of 2 pictures that show a large amount of white dots.
I'm hoping someone will recognize the issue and help me overcome all of this

Myxine said:

a pile of 120 film that I have shot over the past years. The rolls are stored in a closet, at room temperature - I live in Louisiana but the AC prevents the temperature and humidity to be too bad inside.

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Myxine said:

The rolls have been shot around 2 years ago

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OK, based on this, I bet that the problem is some kind of backing paper offset, where the backing paper (likely the ink on it) has interacted with the film emulsion. It's even possible we're looking at small bacterial colonies that have managed to grow in the years the film has sat around.

It's probably not a very good idea to keep exposed but unprocessed 120 film around for so long. Not that it helps much, now, but I'm actually not very surprised that you run into a problem like this and I really expect it to be due to the combination of backing paper (which can have contaminants itself, but moreover also acts as a reservoir for moisture which can contribute to further problems), time and humidity.

I think the best you can do is process the remainder of your film soon and just hope for the best. Some rolls may be better than this one, some may be worse; some may show entirely different patterns of degradation. But I do expect that you'll run into a couple more problem rolls if you have more of this old batch sitting around.

I would vote for backing paper issues.

(Koraks beat me to it...)

I think I see white spots on the positive which means black spots on the negative. I too would blame the backing paper either in storage before exposure or in the case of long delayed development after exposure.

I have a fair amount of b&w 120 unexposed stock in refrigerator storage I bought about 5 years ago. Thought it was a good idea to stock up, only I never shot at the rate I intended...

Now, it's starting to concern me. I need to test it soon...

Thank you for your reply. The backing paper was one of my hypothesis as well. In the past I had kept exposed film in the freezer but it ruined the film too. I thought keeping it in our closet was a safer bet but it looks like it wasn’t.

In a way I m kind of glad that this is not really an operator mistake, since having a baby did not put me in a position to develop the film.

I did observe some other rolls being much less affected but still showing some white spots (more in the sky, somehow) from the old batch.
I’ll keep going through it and hope few meaningful pictures are affected.

Myxine said:

white spots (more in the sky, somehow)

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I noticed this, too, in the second example. It's interesting/puzzling as you'd expect these defects to show up regardless of image content.
If there's a consistent relationship between the image and the defects, also (especially) in 'flat' scans with no selective contrast adjustments, I'd love to see more examples of this. It would cast doubt on the suspected causes.

To me this looks like a massive amount of air bells that got trapped during the first stages of development. The dark ring around the white spots is a strong indicator. Perhaps there is some relation with the quality of the water you are using, but after pooring in the developer you should tap the tank a few times on the table surface to dislodge the air bells.

But if you want to know for sure: send the film to Ilford and they will have a closer look at it.

Huub said:

The dark ring around the white spots is a strong indicator.

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If these were negatives, then maybe. But since they're positives, the core of the defect is plus density on the negaitve, and thus not an air bell that impedes access of the developer to the emulsion.

So, if they are white spots on the positives (that is what your examples appear to be), then it's black spots on the negatives... and they were noticed on film that had been sleeved and stored, but not there when you processed them?

Andrew O'Neill said:

and they were noticed on film that had been sleeved and stored, but not there when you processed them?

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Seems like they're freshly processed; the long-term storage was in unprocessed form, which likely contributed to the problem.

I can only assume there are black spots on the negatives, I would need to put them on the enlarger to be able to notice them. I looked at them with a loupe but could not see anything.
I scanned the films 48h after processing them (just a little time to flatten the negatives)

I usually give a few good "raps" on the tank to dislodge air bubbles. At this level of air bells, one would think I developed with La Croix or some other fizzy water

I recently went through a prolonged battle with black particles on negatives (i.e., white spots on inverted scans) on both B&W and color negatives. I meticulously tried about a dozen different changes to my process, including: trying different water (distilled, tap, filtered tap, etc.), pre-rinse versus no pre-rinse, acid stop bath versus water stop, changing fixer brands, hypo-clearing agent versus none, different rinse aids versus distilled water only, etc. I even constructed a film drying cabinet with filtered air intake and a heat source. I tried each solution by itself but none of them worked. The thing that ultimately solved the problem was using longer fixing times (8 minutes for B&W and 10 minutes for C-41) and using all fixer one-shot (which I already did for C-41). Admittedly, these strike me as unusually long fixing times, but it's the only thing that definitively solved the problem for both film types, so that's what I've been sticking with.

All that aside, and with specific regard to your spots, they have the characteristically fuzzy, equant shape that spots do when they're caused by interactions with the backing paper. By comparison, my fixer-related spots were generally more randomly sized and had very sharp boundaries. The black haloing in your spots is also, in my experience (e.g., with 120 rolls of Rollei Retro 80S), another indication that this is likely a backing paper issue. The problem is inherent to certain B&W films and can be produced in many others by storing them in a refrigerator or freezer. The underlying phenomenon is reportedly related to backing paper inks and rapid humidity changes. I'd start by not storing B&W film in the cold, if you can get away with it.

(As a side note on drying film: I discovered one doesn't need forced air or heat in a film-drying cabinet. What you really need is humidity. The humidity where I live is typically ~30%, which dries the film base too quickly and prohibits the surface water from fully sheeting off the film. As a result, you end up with rinse-aid scum on your negatives. My approach now is to pre-steam my drying cabinet with boiling water a few minutes prior to hanging my film, which drives the humidity up to 80% initially. The film takes a little longer to dry, but... cleanest negatives I've ever seen.)

Thank you, Scott, for your detailed answer. The main hypothesis is then backing paper adherence or microorganisms growing on backing paper - which in the end have the same root: the film was stored for too long. Even though it is in a dark closet at room temperature, the fact that the atmosphere is so humid here might not be conducive to prolonged storage of used rolls.
I must say that all those pictures were shot in a very dry environment, which makes a large difference in humidity in my area and could add to the issue.