Help Requested: Black Specks Troubleshooting (A Strange And Confusing Tale)

Hi folks,
Been lurking/learning for a while and joined to request some advice. I've shot and developed over 100 rolls of film, and am no stranger to the common mistakes and pitfalls, but lately have encountered an issue that I would like to run by you all before I invest more time, film, and chemicals into diagnosing and testing.

The short version of my story is that I am getting significant black specks all over my negatives. They did not stand out to me when I was shooting largely medium format last year (but they are present), however last fall I got into bulk rolling 35mm film and the enlargement of the smaller negatives revealed significant black specks all over the negative which appear as white "snow" on the inverted scans.

My development process has become about as clinical as I can make it at home. I started using distilled water for the entire process (chem mix [if powder], dilution, final rinse, and wash aid), spending almost a gallon of distilled water per roll of film (I use the ilford method, but the black specks appear with running tap water 10 minute rinses too). I rap the tank after inversions to clear bubbles. I switched to a 10 micron chemistry filter to filter both fresh and re-used chemistry. I started fixing longer, I tried hypo clear. I run the shower till the bathroom is completed fogged with steam and dry my negatives in the shower inside a zippered garment bag that was open and exposed to the steam. Although some rolls/frames were better than others nothing I did reduced the specks to a "normal" amount of dust (eg the same levels I see when I send my film off to a lab). When I inspect the negatives with an 8x loupe I can see the black specks all over. I have used over 7 different cameras, 5 different developers (Xtol, DD-X, Pyrocat-HD, Flic BW&G, Rodinal), and different brands of fixers (llford Rapid Fix, TF-4) and many film stocks (Foma, Kodak, Ilford, Lucky). I have loaded in a dark bag, a dark closet, and (for test rolls) in broad daylight. I deep clean my darkroom equipment and even ran them through the dishwasher by themselves (which had no effect--didn't make things worse or better).

I know this is a post in a B&W topic but this issue persisted (and in some cases was worse) for C-41 development. Digital ICE wasn't removing them (they're baked into the emulsion). Finally I noticed that on the home developed negatives done with plastic reels and tanks these specks are nearly completely absent. About mid-way through last year I switched from plastic to metal tanks and all of my negatives from that point onward have this issue. So I think I found the correlation but I can't determine the cause. I switched to metal to save money on developer and because the film stocks I prefer often get bunched up/creased in the "push" winding for loading it on the plastic reels. When I switched to metal reels (pull winding) I stopped ruining rolls of film during loading (particularly Svema, Foma, and Lucky which have very thin/curly bases), but have many almost unusable rolls of 35mm film due to the specks.

I have included some samples. The blacksmith is T-Max developed with DD-X 1+4. The owl and panda photo is Foma 400 developed with Eco Pro Xtol 1+1. Both were soaked in Kodak PhotoFlo 1.5:200 (which seems to leave the least amount of scum on the negatives but I have these specks whether I use PhotoFlo or not). I am also including an IR scan of a C-41 negative which exhibits the black speck issue most clearly. Out of desperation I squeegeed that roll (Fuji USA 200) and still experienced the black specks. The last image I have included is an IR scan of the last frame of a non-squeegeed roll of C-41 film (Kodak UltraMax 400) which has a ridiculous amount of gunk on it. I have noticed that the specks often (but do not always) accumulate on the lower frames of the roll (as they are hanging). For example the Fuji 200 roll's last frame is ironically nearly pristine. Re-rinsing and re-fixing does not remove the specks.

What do you think is causing this, and why is it worse for metal equipment vs plastic?

Well... it's dirt. Given what you say, it's probably the reel, the tank, or both.

Do you use more than one metal tank? Which brand and model? And are they new or used?

I would prefer to see a scan of a negative.... Are you able to determine which side the black specs are on?

I wondered about the garment bag you use for drying. Could it be shedding whatever it is made of?

Welcome aboard @quigs!
Sorry to hear about & see your dust & dirt problems - as that's what this is, evidently.
Sometimes, it can help to inspect the (scanned) dust / dirt closely to determine shape and size of the particulate contamination. This can contain clues as to the possible causes.

quigs said:

they're baked into the emulsion

Click to expand...

You said this in relation to C41 and I can confirm this is the case; it's very frustrating indeed and usually the problem cannot be entirely resolved. It is possible to re-wash negatives, but it requires mechanical cleaning of the wet film (emulsion side) to get rid of (most of) the dust. This involves a large risk of scratching the emulsion. So once this problem happens, you're more or less stuck with digitally cleaning out the dust on scans, or using physical spotting of prints.

quigs said:

About mid-way through last year I switched from plastic to metal tanks and all of my negatives from that point onward have this issue. So I think I found the correlation but I can't determine the cause.

Click to expand...

That appears to be a correlation, but (1) it's unclear how strong the correlation is and (2) whether correlation should be relied upon for causation.
Have you done any systematic testing of plastic and steel reels to see if the problem indeed follows the steel reels specifically? I don't expect it will, honestly, but it all starts with testing.

Potential causes for the kind of dirt issue you're showing here can include:
* Contaminated water; you use distilled water for making up the chemistry, but how about the wash? You mention tap water there. Small dirt can occur in tap water systems, for sure.
* Contamination in utensils or vessels that come into contact with your process water. To give you an example, I battled a really persistent contamination issue once and it turned out to trace back to scale buildup in a water cooker I used (for 'kick-starting' the warming up of the wash water for color film). I'm not saying the cause would have to be a boiler or heater; consider any vessel, utensil or pipe system your process water comes into contact with. Given the persistence of the problem, it will likely be a recurring or permanent issue.
* Dirt deposited during drying. You mention a zippered garment bag. That's a red flag to me (I agree with @Premier)! Was this bag ever used for garments in the past? What material is it made of? Either way, don't use this. Just hang the film in the shower area. Don't disturb the room until the film is dry. Ensure reasonable cleanliness of the rooms where you handle wet film in.

At least some of the dirt consists of fibrous contamination, so the garment bag would be at the top of my list to eliminate.