Steve, también trabajo con pyro, cual es la formula del TF-4?
Rudolf Leitgeb made me aware of this post and the earlier 2004 post in photo.net. Thank you Rudolf.
In the 2004 photo.net post, Danny Spence wrote:
"The formula seems simple enough with only three dry chemicals -- sodium thiosulfate, sodium sulfide, and sodium bisulfite."
Mr. Spence indicates that he used sodium sulfide. The correct chemical is sodium sulfite. If he did use sulfide this would account for the discoloration and sludge. I have looked at all 4 editions of the DCB and sodium sulfite is specified.
In the second thread (in which only an offensive smell is mentioned) I concur with the conclusion of several respondents to eliminate both the bisulfite and citric acid from the formula. Bisulfite was included in the original formula before papers were sufficiently hardened. Acid is no longer needed and for that matter hardener of any kind, as most papers are over-hardened for machine processing. Those that are not over-hardened still contain more hardener than papers prior to the 1990s.
At the time the first edition of the DCB was written I was using F-24 for large format pyro negatives. I later switched to TF-4 alkaline fixer with a 1 minute running water rinse in place of a stop bath, thereby eliminating both the acetic acid stop and hardener in the fixer. I now use TF-4 for film and paper.
I never tried substituting citric acid in F-24 as I never had a problem with odor and have always tried to minimize the use of hardeners.
My apologies to both Mr. Spence and Mr. Goldstein for having discovered this the hard way, but thank them for sharing with the rest of us. I have just crossed out the citric acid in my mark-up copy of the DCB, as per Mr. Goldstein's recommendation. :sonríe:
Feel free to post these issues on the DCB forum and I will be more likely to see them and respond.
Steve, también trabajo con pyro, cual es la formula del TF-4?
Rmaydana, TF-4 is a proprietary formula by Bill Troop, my co-author of the Film Developing Cookbook 2 (FDCB2). It is available from The Photographers' Formulary.
Bill has created a close version, TF-3, published in the Darkroom Cookbook 4 and FDCB2. In the fifth edition of the DCB that I am working on, several alkaline fixer formulas will be available. In the meantime, the formula for TF-3 from the FDCB2 is:
Ammonium thiosulfate, 57-60%, 800 ml
Sodium sulfite, anhydrous, 60g
Sodium metaborate, 5 g
Water to make 1 L
Working solution: Dilute 1+4 with water
Steve, I am using TF-2 for almost all developments requiring 6 minutes or more, with only water stop bath after development and Ilford method of washing after fixing. My question is, whether this procedure is right, and, whether there would be any preservation issue in future?
Secondly, is TF-3 any better than TF-2? Since, Ammonium Thiosulphate is very expensive here in India, I go for TF-2.
As both of these formulas can be credited to Bill Troop, I have sent your query to him. He says he will try to answer in a week or so. In the meantime, I can say this. The Ilford method of washing was debunked many years ago. It doesn't work. Kodak put forth an alternative method that is almost the same but with a few differences. The Ilford method was based on the Kodak method. My guess is that they tried to make it just different enough not to be accused of copying Kodak. The Kodak method has been proven to work, the Ilford method does not.
It is too involved for me to include it in this thread, but the Kodak method can be found, along with Bill and my commentary on the Ilford method, on pages 148 and 149 of The Film Developing Cookbook, 2nd edition.
If you don't hear from Bill in a week or so, let me know, and I'll remind him.
As both of these formulas can be credited to Bill Troop, I have sent your query to him. He says he will try to answer in a week or so. In the meantime, I can say this. The Ilford method of washing was debunked many years ago. It doesn't work. Kodak put forth an alternative method that is almost the same but with a few differences. The Ilford method was based on the Kodak method. My guess is that they tried to make it just different enough not to be accused of copying Kodak. The Kodak method has been proven to work, the Ilford method does not.
It is too involved for me to include it in this thread, but the Kodak method can be found, along with Bill and my commentary on the Ilford method, on pages 148 and 149 of The Film Developing Cookbook, 2nd edition.
If you don't hear from Bill in a week or so, let me know, and I'll remind him.
Just to be clear, are we talking about fixing film or paper? The thread started talking about fixing paper but you mention a method described in your "film" developing cookbook.As both of these formulas can be credited to Bill Troop, I have sent your query to him. He says he will try to answer in a week or so. In the meantime, I can say this. The Ilford method of washing was debunked many years ago. It doesn't work. Kodak put forth an alternative method that is almost the same but with a few differences. The Ilford method was based on the Kodak method. My guess is that they tried to make it just different enough not to be accused of copying Kodak. The Kodak method has been proven to work, the Ilford method does not.
It is too involved for me to include it in this thread, but the Kodak method can be found, along with Bill and my commentary on the Ilford method, on pages 148 and 149 of The Film Developing Cookbook, 2nd edition.
If you don't hear from Bill in a week or so, let me know, and I'll remind him.
Just to be clear, are we talking about fixing film or paper? The thread started talking about fixing paper but you mention a method described in your "film" developing cookbook.
I've used the Ilford method of paper fixing for over 30 years and from time to time done residual hypo tests and the Ilford method has always tested well. Or are you talking about the Ilford film fixing/washing method with the set number of changes of water? Could you please clarify?
But now, I really wish I could read more about the Kodak washing method, because I have been using the Ilford method to wash my film (slightly modified). Is there anywhere online I can read a description of the Kodak film washing method, or do I need to go begging to borrow one of the books?
per post # 29:
But now, I really wish I could read more about the Kodak washing method, because I have been using the Ilford method to wash my film (slightly modified). Is there anywhere online I can read a description of the Kodak film washing method, or do I need to go begging to borrow one of the books?
Was the description of the Kodak wash method only in the second edition, or is it in the third edition, as well? Thank you.
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