I think that Simon's word should be deemed to be an enlightenment.
These films have an incorporated wetting agent which helps to provide even development and, given a pre-development water bath, that mitigating factor becomes nullified. There really ARE reasons for respecting the manufacturer's caveats. - David Lyga
I am HARMAN I am ILFORD Photo, so speaking to myself :
I have already stated : We do not recommend pre-soaking our films, we do not believe it is necessary. BUT nor, done correctly, should it harm them, the risk is uneven development, but if you use a JOBO fine, if pre-soaking is part of workflow and you prefer it...fine.
I will always take the advice of our technical service staff in relation to our products, they are deeply knowledgeable with decades of service and very hands on.
From a personal perspective I have never pre-soaked.... ever, and never had a problem.
Simon ILFORD Photo / HARMAN technology Limited :
Simon:
Could you review with the technical service staff their reasons for including the following in the data sheet section for rotary processing:
"Follow any guidance given by the processor manufacturer when adjusting process times for these types of processors. However, generally we do not recommend using a pre-rinse as it can lead to uneven development.Without using a pre-rinse the given development times will need to be reduced by around 15% to compensate for the continuous agitation."
This is from the "powder developer" data sheet, but there are similar (although not quite as clear) sections in the film data sheets.
Is this advice particular to rotary processors? Should the advice be made more general? Should it be updated to be in accordance with your posts here?
Thanks
This is where the unevenness happens: during the infusion and diffusion process of developer filling the water saturated film.
Is there evidence for this? Does that mean that those who use a pre-soak and do not experience unevenness are simply lucky. I had thought that Simon Galley had cleared up the "Ilford " controversy about pre-soak in that he modified/expanded on Ilford's thinking which is now that a pre-soak does effectively nothing but doesn't actually cause problems.
Maybe someone knows and can quote exactly what Simon said.
I wonder what is different about those films where a pre-soak is actually advised?
pentaxuser
Its not about the films, its about how the film is covered/coated with developer and the speed its done at. For best results film should be completely covered with developer as quick as possible. That means less than 5 seconds. If you take longer you risk development streaks and/or marks.
I am HARMAN I am ILFORD Photo, so speaking to myself :
I have already stated : We do not recommend pre-soaking our films, we do not believe it is necessary. BUT nor, done correctly, should it harm them, the risk is uneven development, but if you use a JOBO fine, if pre-soaking is part of workflow and you prefer it...fine.
I will always take the advice of our technical service staff in relation to our products, they are deeply knowledgeable with decades of service and very hands on.
From a personal perspective I have never pre-soaked.... ever, and never had a problem.
Simon ILFORD Photo / HARMAN technology Limited :
Based on the above I can understand why I have seen the recommendation that the tank is filled first, left open and then the loaded reel is placed in it. You can't get more instant than that
However here's the devil's advocate now: If it takes 8 seconds to fill the tank the bottom part of the film gets maybe 6 seconds more than the very top with all stages in between getting proportionally less development time than the bottom of the film. However the whole film is covered completely from the eighth second onward. If the dev time is 12 mins 30 secs then bottom of the film has received 12mins 30 secs and the top 12 mins 22 secs.
I wouldn't expect to see a difference in film from a development difference of 6 secs over that kind of time period so what is it about the 6 secs that causes development streaks or marks
There may be something else about the development process at work here that might cause unevenness and streaks but I cannot think what it might be
Thanks
pentaxuser
Thanks for that response RobC. I am sure you are right about short development times. Mine have always been longish ie. 10 mins minimum where 6-8 secs are a very small percentage. I recall that Roger Hicks said that if you want to increase development time to make a difference to a film then at over 10 mins, 15 secs makes no appreciable difference
This brings us back to NB23's response about why a pre-soak leads to problems. Currently my reading of Simon Galley's response is that except in your scenario of short development times a pre-soak is not harmful. I note that in John Tinsley's book on Rotary Processing he recommends a pre- soak as a means of keeping times the same as as in inversion processing. He used to process film for a living and at no point did he warn of pre-soak dangers. If he had experienced problems then why would he recommend using pre-soak for Jobo processors?
I await with interest NB23's evidence of pre-soak problems
pentaxuser
I read this here a lot and I know Ilford says this. Generally I do not pre-wash but lately for my 120 development I've switched to using a Jobo with constant agitation because of uneven processing issues using 120 in standard SS tanks. The Jobo process involves an imperative 5 minute pre-soak. Since switching to this method my uneven process issues particularly in open skies is a thing of the past, and that includes doing so with Ilford. No problems at all.
I pre-soak all my films that I develop in my Jobo, which is all the film I develop aside from those in Diafine, and never have a problem related to the pre-soak. This is per Jobo instructions.
It's a relatively old debate and you hear'never had a problem' from both sides. I had uneven developmenr problems in the Jobo with short presoaks and dropped them altogether.Since then,everythin is fine.I'll continue with the Ilford-recommended no-presoak procwdure.I agree with lford that it is not needed for even development.Hard to argue with success
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