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  1. #41

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    A question sprang to mind last night as I was laying my head down to sleep: When you tone with gold or selenium, are the silver grains being encapsulated as pure silver, or encapsulated in a tomb with hypo inside also?

  2. #42
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    Tom, in some cases, the silver is being replaced! Toning is a complex chemical reaction.

    Hypo is not involved.

    PE

  3. #43

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    Replaced. Hmm. Now, what I know about gold, I assume to be likewise for selenium. Neither is a noble metal, like the noble gasses which can't be made to compound. But they are noble in terms of oxidation. But what about compounding with the chemicals in hypo? If you can see where I am going...if you have to wash a print till the paper fibers fall apart to get the hypo out, then would the selenium (or gold) protect the metallic grains from these residual remnants of hypo? If so, then the only real damage the residual hypo could do is yellowing of the paper. No answer is necessary to this pondering of mine, as the matter has already been hashed to exhaustion. Thanks.

  4. #44
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    Got it, thanks. So the same info applies to TF-5?

    One possible issue - it specifies running water. I don't yet HAVE running water in my darkroom. I use trays of still water and a holding bath and wash later upstairs, for now - it's being built out but got delayed and it may be late this year before I do. I'm pretty sure that should be fine post-fix, but it sounds like it really wants a running water stop.

  5. #45
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    Tom, the gold replaces silver and the selenium forms a salt with silver ion. These are complex issues that do not involve hypo.

    Roger, TF-4 and TF-5 have similar washing parameters. See the sheets for some of the differences. I cannot remember them OTOMH.

    PE

  6. #46
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    Good enough, got it PE.

  7. #47

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    The instructions are very similar for TF-4 and TF-5 but there is an important difference. TF-5 can be used with a regular acid stop bath. If you are using TF-5 I would go with that if you don't have a running water rinse available after development.

  8. #48
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    Even better - I normally use a citric acid stop with regular acid rapid fix, so I can just go on using it with TF-5.

  9. #49
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    After extensive testing, I have found that TF-4 can be used with an acid stop bath as well.

    PE

  10. #50

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    Interesting. Thanks for the update.

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