film...on film

[Percy]

Hi.

I've noticed lately that after developing, fixing, washing and drying 4x5 sheet film, there is a residue of some sort left on one side of the film. This....film, if you will, is like a haze, and wipes of very easily, sort of like condensation being wiped from a mirror or window.

Anybody know what this might be, or, better yet, how to get rid of it?

[Andrew O'Neill]

which film are you using? Are you using photo flo? Once I was using too strong of a solution and film dried with a haze.

[Percy]

tmax 100 and fp4...
and photoflo

[Donald Qualls]

First rule with PhotoFlo, in my experience (and this hasn't changed in about 35 years, AFAIK): use about half what Kodak calls for. I use it 1:500 instead of 1:200, and it's just right; the water sheets off the negatives nicely, and it dries clean enough that even 16 mm negatives still look good. You *can* save and reuse the working solution, though I don't (I use it for one session, which is up to four rolls or half a dozen sheets, limited by my population of clips for hanging and tubes for developing); toss it when stuff starts to grow in it.

And if you're not already doing so, use distilled water to mix your PhotoFlo. IMO, you should do so for the final wash stage, too, to avoid mineral deposits when the water dries on the film surface.

[paulr]

That last thing that Donald said.

photo flow breaks the surface tension of the water, so more of it drips off, and so the water that remains doesn't stay in little droplets ... but it doesn't magically make minerals and impurities in the rinse water disappear. If they're present, some of them will stay behind when the water evaporates.

[Al D]

Most of my experience is with 35mm and 120 formats, but I've developed several hundred rolls of film by hand and I've concluded:

- It's a good idea to mix your wetting agent (Photo-Flo, LFN, FormaFlo, whatever) using distilled water.

- It's a very good idea to use much less Photo-Flo than Kodak recommends. I'd go so far as to suggest 1:2000 or an even greater dilution. I don't Photo-Flo any more. Instead I use Photo Formulary's Forma Flo with 3 drops per 400 ml working solution.

- I would agitate the film quite aggressively in the wetting agent for 2 minutes.

I just processed my first 4x5 sheets yesterday and that same methodology appears to work for sheet film just fine.

[Metod]

Hi Percy

Is it kind of whitish residue wiped easily with the wet fingers? It just happened to me as well. Quite scary seeing it first time. Later I found out that Kodak advises not to use Tmax dev. with sheet film.

Metod

[Glenn Thoreson]

PhotoFlo can cause more problems than it solves if you use too much. Kodak's recommendation is way too much. Even with hard water, 3 or 4 drops in a quart of water will usually suffice. And don't get it on plastic reels.