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  #11  
Old 21st February 2017, 07:21 AM
Martin Rick Martin Rick is offline
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I think it is an error of terminology to refer to an alkaline bath as a "stop bath". At best it dilutes the remaining developer rather than deactivating it.
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  #12  
Old 21st February 2017, 08:09 AM
JOReynolds JOReynolds is offline
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Quote:
Originally Posted by fotofundi View Post
...it all worked and I have been very happy with the results so saw no reason to change, or become involved with pointless debates.
Point taken
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  #13  
Old 21st February 2017, 12:54 PM
fotofundi fotofundi is offline
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Quote:
Originally Posted by Martin Rick View Post
..... At best it dilutes the remaining developer rather than deactivating it.
I'm curious, do you have empirical evidence to support that?
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  #14  
Old 21st February 2017, 04:24 PM
Mike O'Pray Mike O'Pray is offline
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fotofundi, as far as a formula goes, I note that Peter Hogan is still listed here under the "Friends" section and there appears to be a way of contacting him via an e-mail, although I have no idea if that will prove a valid route or not. He hasn't had a presence here since March 2011.

Mike
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  #15  
Old 21st February 2017, 07:31 PM
fotofundi fotofundi is offline
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Thanks for the tip. I'll give it a try.
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  #16  
Old 21st February 2017, 10:45 PM
Mike O'Pray Mike O'Pray is offline
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A google search reveals threads from both FADU and APUG. If anyone wants a formula it is given in the APUG thread "Alkali stop - is it a myth" which my Google search brought up

In the same set of threads produced by the Google search there is a post in APUG by a Canadian who claimed he had asked Peter for evidence and was somewhat peeved that he never got a reply. Several other appeared to express scepticism, including Photo Engineer(PE) who had spent most of his working life at Kodak as an chemical engineer

Dave Miller, late of this forum and one of its founders who appeared to be a champion of Peter Hogan's chemicals, made several posts on this matter. What follows is my interpretation only of what I think he appears to be saying but he was asking others here if they had detected any difference as a result of using alkali fixers or stop bath. I think he was trying to decide if there was evidence from others' experience that alkali stop bath was beneficial

As I said before, a search should help anyone to decide on balance if an alkali stop bath is a real benefit.

Mike
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  #17  
Old 22nd February 2017, 08:43 AM
fotofundi fotofundi is offline
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Thanks for the information Mike - I hadn't realised there had been so much information/controversy/argument over the use of alkali stop bath/fixers in the past. (I don't spend much time on User Forums - this has been an exception)
In this instance, thanks to your suggestion, I found quite a lot of interesting information - in particular from Photo Engineer (PE) and Sandy King.
Sandy King used an alkali fixer back in the early 2000's but had run tests on the use of acid fixer with Pyrocat-HD and found that providing it was only mildly acidic he found no discernible difference in the staining.
I also found the suggested formula for an alkali stop bath, and discovered I already had it in my copy of "The Film Developing Cookbook" - all underlined by me in pencil years ago!!!
I HAD looked for one in my early copy of "The Darkroom Cookbook" but there was no mention of anything there - I really MUST get an updated edition.

David

Last edited by fotofundi; 22nd February 2017 at 08:52 AM.
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  #18  
Old 4th March 2017, 11:23 PM
Stocky Stocky is offline
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I doubt that acid carry over from the stop to the alkaline fixer would affect the fixing adversely. If it makes the fixer less alkaline or close to neutral you would still gain the benefit of choosing that type of fixer. Fixers work much the same over a wide pH range. In the case of fibre paper fixer you would probably discard it long before pH became an issue anyway.

Personally, I use dilute sodium metabisulphite as a paper stop because I think it is more compatible with my neutral fixer BUT it smells of SO2 and is unsuitable for an open tray darkroom. I use a Nova vertical slot system and a reasonable extraction system.
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  #19  
Old 6th March 2017, 08:32 PM
fotofundi fotofundi is offline
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I haven't done any printing for about 12 years, my use of alkali solutions has been solely for processing film. When we designed our house -15 years ago - I included a sink, water and an 'enlarger bench' in my study. By the time we moved in, my darkroom days were over. I had been scanning my negs and learning how to use Photoshop while we waited and found I could get a better print that way than I ever acheived in a darkroom.
I still love using film and processing it, but have no regrets leaving the darkroom part behind.The 'enlarger bench' is now my scanner and printer bench while the sink and running water are used for film processing - and I can do everything with the windows open and the sum streaming in.
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