Strange precipitate forming on film as it dries

Unfortunately in Afghanistan I have all sorts of oddities and hugely variable water quality, but here is something I can't figure out.

As the film comes out of the wetting agent, with a thortough wash beforehand, it is perfectly clean. I hang it up and as it dries a white precipitate forms. Some show as small white specks and others as tiny flakes, rather like tiny pieces of thin dried skin. If I wash it gently under running water using the edge of my fingers to dislodge the precipitate and go thru the wetting agent again, it dries perfectly clean.

When I changed both my fix and wetting agent mixture (where I thought the problem might have arisen) the same problem reoccurred with a different film put through different developer. The problem was fixed with no trouble as explained above.

This issue originally occurred a week ago (all this has been while film testing) on yet a third different film and when I looked at the original container of wetting agent solution, a precipitate had clearly formed in the solution coating the edges and base in contact with the solution. I threw it out and rinsed the container thoroughly. With the two new episodes there is virtually no precipitate in the wetting agent solution, though I can see a couple of flakes and wonder if it is beginning to form again. Thi first batch sat in its container for a week before I came to replace it just now, which is when I saw the precipitate.

Things that have remained constant:

• The boiled water stock (from bottled filtered water - the only truly clean water I can get here) I have been using to mix the developer.
• The source of the water used for the stop and fix in all cases.
• The bottled water once again used in the wetting agent solution.

Any thoughts? As I say, the precipitate is not there on the film when you hang it, but it is 20 mins later!

All film has been thoroughly washed in all cases so dev/stop/fix should still be about. Everything looks clean and clear.. until it starts to dry.

Try filtering the chemicals before and after using. There are filters with screens at the base of the funnel or use coffee filters.

Steve

Put some of your bottled water in a clean glass and let it evaporate. That way you will see how many minerals are dissolved in it. Bottled drinking water is not usually mineral free.

The bottled drinking water we buy here in Turkey has a high mineral content, I'd expect yours to be similar.

Your best bet is a small jug filter used for drinking water for the final rinse water & wetting agent, I paid £10 for mine in the UK about 4 years ago, and a bit more for some spare filters.

Ian

Sounds to me like too high of a wetting agent concentration.

-30-

panchro-press said:

Sounds to me like too high of a wetting agent concentration.

-30-

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That's immaterial this isn't a wetting agent issue.

Ian

I second to mineral content. My tap water acts alike. Everything clear and clean while wet, white specks when dried. Just around water spots left on the film.
Found the solution to be in final rinse in distilled water, after wash in tap water.

A rinse in a weak white vinegar solution, or gently wiping negatives with a soft cloth wet with vinegar should remove it if it is calcium.

Ian Grant said:

The bottled drinking water we buy here in Turkey has a high mineral content, I'd expect yours to be similar.

Your best bet is a small jug filter used for drinking water for the final rinse water & wetting agent, I paid £10 for mine in the UK about 4 years ago, and a bit more for some spare filters.

Ian

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Ian,

Are you referring to the kind of filtering system that one uses while backpacking???
I am thinking of the kind that one pumps water from a stream or lake for example and the resultant is drinkable once boiled or treated with chlorine tablets.

Maybe you should try plain distilled water instead of bottled water.

Distilled water for very solution including washing would be a real pain. I think I have discovered where the issue came from but dont know the source as such. Because the tap water here can be full of debris, what I do is put the tap on and let the water pressure back off until it is a trickle, I then fill 1.5l bottles very slowly, which tends to result in remarkably clean water. I use this for stop, fix and all but the final rinse. I then use filtered bottle water (not mineral water) for the final wash (I use the Ilford method rather than continuous flow) and wetting agent solution. I also filtered bottled (non-mineral) water for the developer. No problems until now...

It turned that one of my 'wash bottles' had some contamination. I can only surmise that this gunk ended up on the film and stuck to it and that I did not notice it until the film started to dry each time as while the film was very wet, the gunk was well coated with water and translucent. I probably did not notice this gunk sitting in the base of the bottle and re-used it several times, with some of it coming away and ending up on the film during washing. The only thing I can liken it to is the crud you get around a rice cooker when you cook rice rich in starch (but not as bad of course!). I have no idea where it came from in the first place.

That teaches me a lesson: inspect all bottles right into the dimples in the base before filling and also again before use. I normally do and when i dont this happens! At least it could be washed off.

Thanks for your thoughts all and I will let you know if the problem perists despite throwing out the affected bottle.

Tom Stanworth said:

That teaches me a lesson: inspect all bottles right
into the dimples in the base before filling and also
again before use.

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Easily done if the bottles are of Clear glass or plastic.
And the reason I always direct the use of same. Dan

dancqu said:

Easily done if the bottles are of Clear glass or plastic.
And the reason I always direct the use of same. Dan

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So much for the thread about obtaining brown bottles. PE posted on that thread that if the bottles are keep in dark places, the bottles need not be brown.

Steve

Sirius Glass said:

So much for the thread about obtaining brown bottles.

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Amber. Colorless as well as Amber Boston Rounds are
very available in narrow and wide mouth and there
is a selection of caps. Amber is the traditional
darkroom choice. Amber or colorless the
glass is clear. Dan

Wipe your negs, as soon as they come out of final rinse. I use a car windscreen wiper rubber cut down about 4" and rubber glued to a piece of timber. Make sure it is perfectly clean, before using. Run down the film once each side with gentle pressure.

The film dries quicker, and doesn't leave any water residue.

BradS said:

Ian,

Are you referring to the kind of filtering system that one uses while backpacking???
I am thinking of the kind that one pumps water from a stream or lake for example and the resultant is drinkable once boiled or treated with chlorine tablets.

Click to expand...

I'm not Ian, but I have a Pur Hiker water filter which is rated for one micron filtration. I'd expect minerals to pass right through my filter, even though large viruses and all bacteria are stopped. A more common activated charcoal water filter would be more likely to absorb dissolved minerals.

I agree with a previous poster. Mineral water is supposed to contain minerals. Bottled water is just water in a bottle. Distilled water should be pure water.

I do not wipe the negatives, I let the water/PhotoFlo flow off the film. Never had spots or streaks.

Steve

I do used clear bottles for holding the wash water, but gunk can be easy to miss when it settles in the crinkles in the base. You have to peer into each base, invert, check for movement of particles etc. I will be so glad when done here as film D&P is a nightmare.

I too wash, use wetting agent solution, then hang. Dont get drying marks except sometimes with D100/FP4+ which for reasons I cannot fathom seem very susceptible.

davidst said:

Wipe your negs, as soon as they come out of final rinse.
I use a car windscreen wiper rubber cut down about 4" and
rubber glued to a piece of timber. Make sure it is perfectly
clean, before using. Run down the film once each side
with gentle pressure.

The film dries quicker, and doesn't leave any water residue.

Click to expand...

I've a Jobo eight blade expressly designed for film squeegeeing.
Very satisfying and film does dry Fast. The same squeegee is
available under other labels.

I make sure the film and squeegee are both dripping wet
with 1/2 strength PhotoFlo prior to applying. Dan

I would suspect it is calcium-carbonate deposits try rinsing with a dilute acid wash to remove them and then follow with distilled water.

dancqu said:

I've a Jobo eight blade expressly designed for film squeegeeing.
Very satisfying and film does dry Fast. The same squeegee is
available under other labels.

I make sure the film and squeegee are both dripping wet
with 1/2 strength PhotoFlo prior to applying. Dan

Click to expand...

I have the Jobo also and never ever had a scratch.

jeffreyg said:

I would suspect it is calcium-carbonate deposits try rinsing with a dilute acid wash to remove them and then follow with distilled water.

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I suspect you are right. Looks about right.

subsequent rolls have been fine now that everything is clean and suspect solutions tossed out. Can't fathom why one bottle of wash water was so severely affected when the remainder were fine, but then again there is a lot about Afghanistan that is a mystery...