How do I produce clean negatives?
With quite a few year's of darkroom experience behind me I am a bit embarrassed to ask, but: Can you show me how to produce clean negatives, ie, negatives that are free from lime marks, please?
I usually give my negatives a final rinse in de-mineralized water with a tiny drop of detergent (after normal rinse, which is in tap water), but my negatives almost consistently come out with lime marks when dry.
I don't use a squeegee, however I do wipe excess water from the film using thumb and forefinger. Is this OK, or will a squeegee (or any other means) be a better option?
Thanks in advance!
The last wash I use on my negatives is in distilled or filtered water. I do not wipe the negatives, just a gentle shake before I unroll the strip which I just hang up in the darkroom and leave overnight to dry.
The water that you are using cannot be de-mineralized if it is leaving lime marks. Are you sure that they are not detergent marks?
I use a final rinse in water with a few drops of Kodak PhotoFlow. I use about half the recommended quantity of PhotoFlo - too much, and the PhotoFlo itself can leave a residue on the film.
For years, in our former home, I used water that I took from a dehumidifier in the basement. I passed the water through a coffee filter to remove any dust particles that might have gotten into it. Since water captured by a dehumidifier is essentially distilled water, it had very low mineral content.
In our new home we don't need a dehumidifier. But we do have an ion exhange water softener and a reverse osmosis drinking water filtration system that produces water that is free of minerals and dust. I find this works just as well as the distilled water in the old place.
Years ago I also wiped my film (35mm) between a couple of fingers that I had soaked in water treated with PhotoFlo, but I found that I got lots of scratches. (Rough fingers?). So now I just hang them up in a drying cabinet and let them dry.
My drying cabinet is a DIY wooden cabinet with a fan that pulls air in through a filter, and then flows it past a 200w light bulb and into the chamber with the film. It dries film in half an hour with no dust at all.
By lime marks I assume you mean drying spots. Two rinses with 1 minute soaks may be required. Distilled water may be required rather than de-mineralised.
Use the full recommended quantity of wetting agent. I find small amounts do not work as effectively, but others will disagree.
I rinse with a plastic ear syringe from the drug store filled with the used final bath after the film is hanging.
Rinse the syringe when NEW very very well and before and after each use. Dry in the mouth of a bottle so as to drain completely.
No squeege, sponge, fingers, or wiping are required. All devices will pick up a piece of debris sooner or later and scratch the film end to end.
Use a water filter in the line and air filter in the drying space. The carbon filter drinking filters like Brita leave small particles and do not work.
Best not to reuse fix or other chemicals or filter thru a Bounty towel if you must. Use glass bottles rather than plastic as they can be cleaned.
Your problems will disappear.