I've only noticed pre-soaking doing some damage when done for an insufficient length of time. If the emulsion is not thoroughly pre- soaked, subsequent development may not be even. I noticed this with pre-soak times of less than 1-3 minutes, and hence, I recommend a minimum pre-soak time of 5 minutes to be on the save side.
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P don't print this e-mail unless you really have to On Apr 30, 2010, at 00:25, Richard Knoppow wrote:
----- Original Message ----- From: "Tim Daneliuk" <tundra@xxxxxxxxxxxxxx >To: <pure-silver@xxxxxxxxxxxxx> Sent: Thursday, April 29, 2010 3:09 PM Subject: [pure-silver] Re: Pre-soaking filmOn 4/29/2010 5:05 PM, harry kalish wrote:Quite awhile ago, Ilford stopped recommending a pre-soak because theystarted building a wetting agent into their film. But it gave meconfidence to continue the pre-soak, with the ritualistic tapping of the daylight film tanks on a firm surface to dislodge air bubbles from thesurface of the film. HarryWith this sort of thing, it's probably better to be consistent than toconstantly look for the "right" way. I started presoaking years ago because I believed (rightly or wrongly) it would improve consistency, particularly with short dev times - say with a fast acting developer like D-76 straight and N-3 processing. At this point, all my calibration is built around it and I don't much feel like changing my ways and recalibrating everything because of new fashion.Jobo recommended pre-soaking for their rotary processors, it's necessary with them to insure uniform development. Kodak also recommends pre-soaking where several sheets of film are to be developed in a tray, it prevents sticking and, again, insures uniformity. However, it probably makes little difference in other kinds of processing. I doubt if it does any harm but the induction time _is_ affected and must be taken into account when determining the final development time. There may be some wetting agents in some films which will be washed out in a pre-soak. I've never seen any confirmation of this in any literature.It is good practice to apply rapid agitation at first.I don't consider D-76 rapid acting. Compare its times to some older developers like DK-50 or D-61, the later a once standard photofinishing developer.-- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ====================================================================== To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.
