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  1. #21
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    Initial work on TF5 included Amidol and Azo paper. In fact, that was a basic comparison point with my Azo type emulsion taught in workshops. So, that looks pretty good. The Formulary sends me just about every on-line query (e-mails), so that I can reply. I pretty much don't hear of any of the telephone comments or questions.

    I suggest that your real fix and wash times be adjusted based on retained silver and hypo tests. It is impossible to predict these times accurately because of differing water supplies world-wide. Therefore the fix times and wash times given are generous.

    I have fixers that fix in 15" and wash completely in 30" but I would not give out the formula because it is too chancy. It is very dependent on work flow and water supply. The times I give are real, and the proof is in having 5+ years of keeping to prove the quality of these prints.

    PE

  2. #22

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    Quote Originally Posted by Mahler_one View Post
    I had the same reservations Michael, and that's why I posed the question to Ron. I think most of us would agree that Ron's knowledge of photochemisty would surpass that of most of us. However, I called Formulary last year, and asked about the affect of TF5 on Azo papers developed in Amidol. The person who answered was unable to provide an answer, and until the affect was known, suggested that it would be best to eschew the use of TF5 when using such materials. Perhaps Ron would like to chime in again?

    I wonder about the wash times.....Ilford's permanence sequence using their Rapid Fix does not indicate that the wash time with FB papers needs to be inordinately long. Is Ilford Rapid Fix acidic?
    I don't have any reservations though. I'm saying TF5 is great, end of story.

    Yes Ilford's Rapid fixer (an excellent product) is acidic. Remember, Ilford's permanence sequence includes Hypo Clearing agent to help keep the wash time short. What I'm saying is that with most papers if you use a non-acidic fix you get shortened wash times without HCA, so the process is somewhat simpler. Not the biggest deal, but just something worth noting as a difference in process.

  3. #23

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    Ilford Rapid Fixer is indeed acidic.

    http://www.darkroom.ru/info/manuals/...manual_eng.pdf

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  5. #25

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    OK...thanks...and thanks to you Ron as well.

  6. #26
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    Well, thanks. And, you may note that hypo is about 6.5 - 8 in that reference above. TF5 is pH 6.5, nominally at the point of best stability of Hypo.

    It is very stable. One of the most stable fixers you will find.

    Thanks for posting that. I hate to toot my own horn!

    PE

  7. #27
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    So TF-5 (alkaline), in theory requires less wash time than Rapid Fixer (acidic)? And it fixes fiber prints in a minute but needs 10 minutes to fix film? And overfixing prints is bad because it takes longer to then wash the print?

    I appreciate all the chemistry knowledge available here, but I'm getting a little lost in it. Very willing to learn but please speak to me as though I'm a drunken third grader with a less than rudimentary understanding of the the universe.

  8. #28
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    TF5 is not alkaline. It is near neutral (pH 6.5 AAMOF).

    As I said above, fix and wash times are generous and you should determine them yourself based on workflow and water supply.

    PE

  9. #29

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    pstake: TF-5 is approximately neutral (actually slightly acidic) at pH 6.5. pH7 would be exactly neutral. TF-4 is alkaline.

    I'm not a chemist either but basically it is easier to wash an alkaline solution out of the paper than an acidic one, and standard commercial rapid (and non rapid) fixers are acidic.

    Regarding fixing time, generally yes film takes longer to fix than paper.

    Overfixing prints can increase the required washing time because the longer time in the fixer means there is more time for the fixer to penetrate the paper base. This is why the Ilford archival sequence with calls for a rapid fixer, requiring a relatively short fixing time - which means washing can be faster.

    Another reason to avoid leaving either film or paper in standard fixers for excessively long periods is the fixer will start to bleach the silver in the developed image.

    But remember, underfixing is bad. Better to slightly overfix than underfix. Best is to do it properly, which is why it is important to use fresh solutions for the recommended times.

  10. #30
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    Ok ... thanks for the rundown, Michael.

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