Question About Wetting Agents

APUGuser19 said:

I've used a few drops of Photo Flo in a tank full of water and let it sit 5 or 10 minutes for 45 years. All kinds of water--city water and nasty well water. Never had a single problem. Never squeegeed or wiped the film either. Just soaked it and hung it up to dry. Nary a problem. I don't get it. Strange thread. I see these photo flo type threads all the time, and it doesn't make a lick of sense.

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I think it depends on where you live my friend. I develop my film in Holland. The water is so hard, that if I don't use a special salt in the dish-washer it gets ruined in less than one year. If I don't wipe water from the shower or the kitchen bench, I get stains that cannot be removed. If I do not use clean water for the final rinse, I get stains.

Photoflo 200 dilution is 1+200, that's 5 ml per liter or 19 ml per gallon (US), there are (were?) stronger concentrates available at one time. We used Photoflo 600 at the college lab and I understand that there was a Photoflo 1000 available for photofinishing and cine processing operations. Don't use any kind of mechanical squeegee, sooner or later, probably sooner, you will scratch the heck out of your film. I use two fingers, first dipped in the Photoflo and then run down the film once. One of the reasons I prefer shorter 35mm films is that my arm span is not quite 36 exposures long and I used to have to cut 220 rolls in half after processing so that I could squeegee the film. Reusing Photoflo is false economy, things, horrible stinky things, grow in used Photoflo (unless you add some formalin). I am going to try a centrifuge (salad spinner) to get the last rinse water off my films, some folks say it works very well.

MattKing said:

There is a typo in my post above. I meant to post: "It is far more difficult to reliably and repeatably measure 2.5 ml of stock solution and then dilute it 1 + 199 (also giving 500 ml of working solution at a 1:200 dilution).

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An eyedropper as can be purchased in your local pharmacy is designed to deliver a standard drop of liquid. In apothecary measure there are ~20 drops per ml. So it is easy to measure the correct amount of PF. I have found that 2-4 drops per 250 ml of water is ample to reduce the surface tension and avoid film spots. If I use Kodak's recommendation I get greasy spots on the film.

To a litre of distilled water, I add 50ml 91% Isopropyl Alcohol, and 1ml of Fuji Drywell.