Water Spots Observation

[Kevin Crisp]

I'm passing this observation on in case somebody finds it helpful.

I hate water spots, and use Edwal LFN and distilled water. It works pretty well, best results were using half the dose recommended on the bottle for distilled water. Using distilled water made sense to me since there would be fewer dissolved solids in the final soak that might leave spots. But I still got some. which you can see but which rarely show in a print with a diffusion enlarger.

This weekend I shot two rolls of film that had no intrinsic merit other than being tests. (One was Ilford 100 speed, long expired, the other Tmax 400 long expired.) In one case a meter and a lens on a camera was being tested and the other to seek if I fixed the light leak I mentioned last week in a Graphic roll film back.) So my darkroom processing was a bit more slap dash than usual since the rolls were never going to be printed. I did wash them normally and when it came time to hang them up to dry I figured I wasn't going to waste distilled water on them and I used tap water instead. I added 4 drops of the LFN to one quart of tap water, which the bottle recommendation for tap water. Our tap water isn't particularly hard and we don't have a water softener. I just hung up the rolls with no effort to squeegee them.

I ended up with totally spot free negatives, much to my surprise. They look perfect. Better than I ever got using distilled water. I repeated and got the same result. I guess I'll start using tap water on my sheet film.

[domaz]

It probably depend a lot on your water source but I have found I don't need any kind of distilled water for final rinse here either. Our water comes from a river and it considered one of the best water sources in the nation so YMMV. When I used to live in the middle of the country water spots were common and that water either came from a well (water was quite hard) or the Mississippi, so water spots were common.

[Pere Casals]

+1

Also distilled for stock developer can be good for other reasons, potentially better shelf life and it may prevent dichroic fog if using TMax non RS developer with sheets, aganist datasheet recommendations.

Distilled final rinse prevents problems with tap water borne particles and drying marks, in many places tap water quality varies depending on season, recent rains...

YMMV

[LabRat]

Kevin, one plus this year is LA water is better due to the higher rainfall last winter, and not the sludge we were getting from the lower reservoir water we were getting during the drought years, so good times...

But it does matter how far from the reservoir one is located, as when the water travels further in the system, there are older rusty mains, more construction along them, cars hit fire hydrants, road/construction vibration etc...

In one lab near LAX (end of the system from Hollywood Reservoir), there would be handfuls of sand, rust, particles, and slime in water filters even after a week of a filter change sometimes, so had to pay attention to it closely...

I had been using the water from the supermarket water filter machines, and use it for the PF step (and chem mixing) for roll films, and it works great!!! But I carefully wipe the base side with a very clean slightly damp photo sponge after PF step...

When I started doing sheet film again, I did not wipe them, and mixed PF from distilled water and just hung them, but noticed (during the drought) that the film can have a slight mineral haze and the bare start of drying marks, but figured that might be held over from the wash step, but a final 10 min soak in a distilled or commercial filtered water bath before PF bath solved the problem...

But I hope we don't have a drought like that again!!!

Steve K

[Pere Casals]

Also, a cheap reverse osmosis ($100) device delivers perfect water.

A good solution, if a darkroom sees some activity level.

[Doremus Scudder]

... I added 4 drops of the LFN to one quart of tap water, which the bottle recommendation for tap water. Our tap water isn't particularly hard and we don't have a water softener. I just hung up the rolls with no effort to squeegee them.

I ended up with totally spot free negatives, much to my surprise. They look perfect. Better than I ever got using distilled water. I repeated and got the same result. I guess I'll start using tap water on my sheet film.

Seems to me that you finally got the right dilution of wetting agent to prevent water spots. There's absolutely nothing about distilled water per se that would cause more spots in comparison to tap water. I'll bet your "water spots" were caused by tiny droplets on your film, caused by the lack of sheeting action from a too-weak dilution of wetting agent. The area under the droplets dries slower than the surrounding area, causing "spots" due to stress on the emulsion.

Try your distilled water with the proper dilution and you'll have the same results.

However, if your water isn't hard enough to leave mineral deposits on your film when it dries, then there's no real benefit to using distilled. Just stick with the tap water. That's how I washed for years until I got to a place where the water has too many dissolved solids.

Best,

Doremus

[jose angel]

Same experience as others above... to me (we have "good" quality water), tap filtering is an unavoidable solution.
Distilled water only for some chem mixes.

[Pere Casals]

tap filtering is an unavoidable solution.

Regular filtering removes water borne particles but it not removes diluted salts (carbonates, etc) that may leave drying marks. A reverse osmosis filter for home will remove a lot of those those salts.

[Paul Ron]

Seems to me that you finally got the right dilution of wetting agent to prevent water spots. There's absolutely nothing about distilled water per se that would cause more spots in comparison to tap water. I'll bet your "water spots" were caused by tiny droplets on your film, caused by the lack of sheeting action from a too-weak dilution of wetting agent. The area under the droplets dries slower than the surrounding area, causing "spots" due to stress on the emulsion.

Try your distilled water with the proper dilution and you'll have the same results.

However, if your water isn't hard enough to leave mineral deposits on your film when it dries, then there's no real benefit to using distilled. Just stick with the tap water. That's how I washed for years until I got to a place where the water has too many dissolved solids.

Best,

Doremus

+1

wetting agent dilution is very important. too much or too little will cause water spots n streaks.

[Willie]

Removed since for some reason it double posted.