Ah, I did misread the 480. It was not sulfite, but thiosulfate.
The developer I use is Amidol. Using a water bath as a stop bath is not an option, as Amidol is such a strong developer that development would continue.
The Bisulfite makes the fixer slightly acidic, which, to my knowledge, insures that it keeps active throughout a printing session, which could involve sending 100 8x10 sheets though the first bath of 1/2 gallon of fixer. We have never had the fixer go bad during a printing session, and we always use the second fixer to make the first fixer. So, rather than the acid deteriorating the fixer, it seems to preserve it.
In re-reading Richard's response, it would seem that for us at least, a slightly acidic fixer would be needed to insure neutralization of our very strong developer.
Also, following what Brett did (the only photographer I have ever seen making a print), I put the print in the stop bath for only 10 or 15 seconds. Then into the fixer. After 30 seconds in the fixer I turn on the viewing light. Evaluate the print, and if it is a keeper, it goes back into the fixer for an additional 3 1/2 minutes, before going into the holding bath. The second fixer is for 4 minutes also.
Michael A. Smith On 4/3/11 8:37 AM, Richard Knoppow wrote:
-----Original Message-----From: "Michael A. Smith and Paula Chamlee"<michaelandpaula@xxxxxxxxxxxxxxxxxxx> Sent: Apr 3, 2011 5:13 AM To: pure-silver@xxxxxxxxxxxxx Subject: [pure-silver] Re: Adding Sodium Sulfite to Sodium Thiosufale. Bogdan, I use an acetic acid stop bath. I then use plain sodium thiosulfate with 15-25 grams added of Sodium Bisulfite per 1/2 gallon or 40-50 grams of Sodium Bisulfite per gallon. Many years ago, when I spent a month with Brett Weston, watching him print most every day, this is what he used. I figured if it was good enough for Brett, who learned to do this from his father, it was good enough for me. Brett used the higher number in the quantity range above. Paula does not like the smell of the Bisulfite when she gets close to it, so she has cut down the quantity with no adverse affect. When the Bisulfite is not used, and there is only the plain sodium thiosulfate, the solution soon gets quite cloudy (though seems to continue working). When the Bisulfite is added, it clears right up. I use a two-solution fixing bath. The first bath only gets the Bisulfite. Then I use a holding bath and at the end of the day I rotate finished prints through a second fixing bath, this time with plain sodium thiosulfite only and no Sodium Bisulfite. I then take the prints directly into a Perma=Wash/Rapid Selenium Toner Solution. I have never had any staining. Using 480 grams of Sodium Sulfite per two liters of hypo seems to me to be beyond excessive. That is a lot of Sodium Sulfite. Mt recommendation is to ignore Anchell's recommendation. Michael A. SmithI think you misread Bogdan's post, it was sodium _thiosulfate_. 240 grams per liter is about standard. I have not heard of using sodium bisulfite in fixer but it would probably serve as well as sulfite but would be somewhat acid. Sulfite and bisulfite for a buffer at near neutral pH. Not important for fixer because it doesn't care about pH but acid will tend to decompose it which is why a large amount of sulfite (15 grams per liter typically) is used in hardening fixers using white or chrome alum both of which must be quite acid to be effective. Where there is no added acid about 5 grams of sulfite is sufficient to prevent staining due to carried over developer. I am not surprized that Paula doesn't like the bisulfite mixture because it is probably emitting sulfur dioxide, the same stuff that gives hardening fixers their sharp odor. No acid it necessary if hardener is not used _and_ the developer is washed out. A plain water stop is OK provided it is sufficient to wash the developer out quickly and thoroughly so that it does not continue to work in the fixing bath. An acid stop will stop the developer but any which carries over into the fixing bath will tend to react with the thiosulfate. The conventional acid stop and acid fix prevents a number of troubles but has a set of vices all its own as does not using them. Alkaline fixing baths serve no purpose whatever. -- Richard Knoppow dickburk@xxxxxxxxxxxxx Los Angeles, CA, USA ============================================================================================================= 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.
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