Pinholes in Efke: a different hypothesis

[Michel Hardy-Vallée]

We have heard or read forever that using a stop bath with Efke/ADOX (25, 50, 100) films was a sure cause of pinholes. Anchell & Troop, for example, argue:

[QUOTE="The Film Developing Cookbook, p.103" ]Acid stop baths can cause pinholes and reticulation with developers that contain carbonate.[/QUOTE]

Today I was developing Efke R25 with the Formulary's Beutler developer kit (yes, I know, I'm too lazy to buy a scale and mix it myself...). Beutler (Neofin Blau) is Metol/Sulfite/Carbonate. My favourite stop bath is Kodak's Indicator. Sounds like a recipe for disaster, right?

Here's what I did: developed the film in Beutler 1+1+10 for 7', stopped in Kodak for 1', fixed in Ilford Rapid Fix 1+4 for 3'. Everything around 20C.

Since I like to "chimp," I pulled the film off the reel right after I was done with fix. I inspect the film: zero marks, zero pinholes. Yippee!

Rinse time now: 20' in 20C water. I put the water maybe a tad strong, but I had a 2L Paterson tank to rinse, so I wanted to make sure that the water was circulating.

Here's little me looking at the film after the rinse: PINHOLES! at places where they were not when I "chimped." And the edges of the emulsion are frayed.

My hypothesis now is simply this: Efke films have fragile emulsions, the coating is not first-tier like Kodak, Fuji, or Ilford, and bound to have small, invisible defects. As long as the film is handled carefully, mechanically speaking, it should be fine (note to self: wash GENTLY!).

But nothing seems to indicate that those pinholes are due to the putative interaction between the alkaline developer and the acidic stop bath. The emulsions are feeble, that's all.

 

[Nicholas Lindan]

Ilford rapid fix is a non-hardening fixer. At one time all fixers for film use incorporated hardeners. Kodak did away with this requirement by using the color film emulsion technology in their B&W films and so now these films can cope with 100F processing temperatures. Ilford followed suite.

Needless to say, you need to use a hardening fixer, and possibly a hardening stop bath, with old-world emulsions. There are also hardening baths that can be used after the fix. The FDC'book has several formulae.

There is no reason not to use hardener in film processing. IIRC, Efke specifically calls out for a hardening fixer in the processing instructions.

 

[Ian Grant]

The EFKE/Adox emulsions today are significantly better in terms of hardening than they used to be when I began using them in the mid 70's, I think they improved them in the late 80's or early 90's.

One problem is these EFKE emulsions are a single thin layer, they were very advance when first introduced in the early 50's and way ahead of other manufacturers in terms of fine grain & sharpness.

In recent years I haven't found a need to use a hardener with these films, but at one time I used to ad Formalin/Formaldehyde to the developer just prior to development which worked wonders.

If you use a developer like Pyrocat the tanning effect of the Pyrocatechin hardens the emulsion slightly.

Ian