Streaks despite final bath in distilled H2O + wetting agent?

JohnSaves · 2017-07-08T18:21:52+00:00

(unbearbeiteter Rohscan) Ich habe den Film in einem Schlussbad aus destiliertem Wasser + Netzmittel gründlich endgewässert. Dennoch diese Schlieren. Gibt...

JohnSaves

(unedited raw scan) I thoroughly rinsed the film in a final bath of distilled water and wetting agent. Yet these streaks remain. Are there any tricks I’m not aware of, or why can’t I get clean images? Do you have any other ideas or tips? It’s really frustrating...

HenningH

Wetting agents contain substances that can turn even the hardest tap water into a suitable solution for wetting. If you use water that is already very soft (there is no such thing as water softer than distilled or demineralised water), the wetting agent has virtually nothing to do and can cause streaks like these. With distilled water, you therefore need an extremely small amount of wetting agent. I use one drop per quarter of a litre of water. ? If you have already used such a small amount of wetting agent, please disregard my post. ;)

Morte

My method for clean negatives: - Reduce the specified amount of wetting agent by 25–50 per cent - After the bath, give the reel a few vigorous shakes until no more water splashes out (a gentler alternative to a salad spinner) € I’ve been doing this successfully for years. It works even with Berlin’s hard water or distilled water.

Wolfgg

Hello John, Are the marks on the coating side or the backing side? If they’re on the backing side, they should be removable with a soft cloth. If they’re on the coating side: rinse the film again in distilled water (without any wetting agent added) and, as Morte suggests, simply spin-dry it. If the marks still don’t disappear, there must be another cause. Regards, Wolfgang

tomsand

So I do it the way I learnt 50 years ago. Add a little wetting agent to normal Berlin tap water (1:200… 1:400), put the film in and leave it there for a minute. Then gently wipe the film between two fingers. AFTERWARDS, however, run it through the wetting agent bath again and hang it up to dry while it’s still wet. You can see clearly whether the water is still beading – if so, you’ve used too little wetting agent – or whether it runs off smoothly. If there really are any limescale residues or streaks left on the back of the film after drying, you can gently rub them off with a soft cotton handkerchief (breathing on it if necessary).