View Full Version : pre-soak question

19-Apr-2005, 13:05
Ilford advice notwithstanding, I find a one-minute presoak using a smidge of Photo-Flo to be more or less essential to eliminate airbells when developing FP4 in PMK. It may just be the well water chemistry or my technique, but without this step no amount or style of agitation seemed to dislodge them from sheet film developed in hangers. Adding Photo-Flo to the developer itself reduced, but didn't eliminate, the problem. The presoak probably slows the effective development rate somewhat, but that has been "calibrated out" of the procedure.

For what it is worth, the late and lamented Kodak Plus-X Professional didn't exhibit the airbell problem.

John Cook
19-Apr-2005, 13:15
I have heard several pyro users state the need for a pre-soak with that developer. In addition, I believe Jobo may require it because of the unique immersion method.

As a dip-and-dunker who has never done pyro, I have never found pre-soaking beneficial. I also never try to fill a daylight tank through the hole in the top with the film inside.

Just did a little math, and my weekly 20 rolls/sheets since the 1960's must add up to nearly 40,000 pieces of film processed without difficulty.

Never too old to learn, however...

Gem Singer
19-Apr-2005, 13:59
Hi Harold,

I'm with John on this one. Ilford claims that they have incorporated a wetting agent into the emulsion and/or the anti-halation backing of their films. Pre-soaking removes that wetting agent and effects the speed of the developing process. Therefore, using a pre-soak is perfectly acceptable with Ilford films, providing that the developing time is adjusted. However, since it is not an absolute necessity, why bother with it?

You state that you are using PMK developer and well water, along with dip-and-dunk agitation (film hangers) and getting a lot of air bells. Gordon Hutchings describes that solution to that problem in his book. Therefore, it is not unique. Since you are able to obtain satisfactory results, merely continue to follow Gordon's recommendation.

CP Goerz
19-Apr-2005, 15:52
EDTA also works.

CP Goerz

19-Apr-2005, 20:43
Presoaking with photoflo is ok, and presoaking in a jobo drum is more than ok, but you should absolutely avoid presoaking with photoflo IN a jobo drum. It can stick tenaciously to the plastic reels, and slowly release into the developer, causing lack of uniformity in the surface tension of the developer, and causing uneven devolopment.

Sounds weird, but I got this straight from jobo when they diagnosed this as my problem. And I wasn't even presoaking with photoflo--i was using it in the final rinse. Enough of it hung on even after washing the tank to cause problems. The jobo tech gave me an elaborate washing procedure to use if photoflo ever came in contact with the reels. I think it involved bleach.

Anyway, for developing tmax, I always found a weak metaborate solution healped a great deal, both for promoting evenness and for removing the dyes.

Brian Ellis
19-Apr-2005, 20:49
I've never used FP4+ but I used HP5+ in pyro with tray development. I started out with a presoak because in "The Book of Pyro" Gordon Hutchings specified a presoak. But I didn't like adding another chance for scratches, etc. with the presoak so I decided to try a few runs without it. Everything seemed fine, I didn't get any uneven development that I could see, so I stopped using it with pyro (and don't use it with anything else).

20-Apr-2005, 12:40
Thanks, Eugene and others!

I have the Hutchins book, and didn't try the metaborate soak because my well water is already alkaline (about pH8 by pHydrion test paper). One of the things that led me to try adding Photo-Flo to the presoak was that after processing, as the water drained from the sheets I could see tiny features on the emulsion that looked like dust. They wouldn't rinse off, and all of the solutions were clean, so I assumed that they were artifacts of FP4 manufacture which increased the propensity of airbells to stick. Whatever it is, it doesn't seem to affect the eventual printed images, so I have quit worrying about it.

Incidentally, we're not talking about much Photo-Flo here; I keep a squeeze bottle of 1% in distilled water for final rinse of film, and about 2--3 cc of this goes into a liter of water for the presoak bath.