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Thread: RA-4 Chemistry

  1. #1

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    RA-4 Chemistry

    i have been working with RA-4 for only a mont now, and was wondering if it is very dangerous. Also, i just bought a 10 liter kit, and only want to make 1 liter at a time, so i divided everything by ten, including the water you add. Will this still work.

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    Ed Sukach's Avatar
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    Quote Originally Posted by nlochner
    i have been working with RA-4 for only a mont now, and was wondering if it is very dangerous.
    No, it isn't. I wouldn't drink the stuff, but - read the instruction sheet... it seems to contain sufficient safety information.

    ... Also, i just bought a 10 liter kit, and only want to make 1 liter at a time, so i divided everything by ten, including the water you add. Will this still work.
    Yes, it will.

    I think it is important to store the unused chemistry properly, to prevent oxidization. A shot of propane - or as I do, butane from a BernzoMatic Mini Torch into the bottles to displace air - has worked - very well.
    Carpe erratum!!

    Ed Sukach, FFP.

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    Several different manufacturers make RA-4 chemistry (or perhaps technically that should be "RA-4-compatible chemistry" for most manufacturers). They don't seem to be absolutely identical. If nothing else, some (such as Tetenal and Paterson) ship the developer and blix both in single bottles, pre-mixed, to be diluted for use; others, such as Kodak and Freestyle's house brand, ship in multiple bottles that you mix together and add water for use. I don't know if these differences are important for either safety or keeping properties -- any comments on this? I do know that the instructions I've read all give different keeping properties for mixed/diluted vs. unmixed/undiluted storage.

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    For many years I used Kodak RA-4 and I found that they are pretty harmless. I recently tried some Tetenal and found that their blix is a bit more caustic.

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    Ed Sukach's Avatar
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    Quote Originally Posted by srs5694
    .... If nothing else, some (such as Tetenal and Paterson) ship the developer and blix both in single bottles, pre-mixed, to be diluted for use; others, such as Kodak and Freestyle's house brand, ship in multiple bottles that you mix together and add water for use. I don't know if these differences are important for either safety or keeping properties -- any comments on this?
    I'm sure that the accomplished Chemists we have here on APUG can give a more well defined answer than I can - but from my observations, the multiple component color developers and blix last longer, protective gas blanket or not. I have purchased NEW kits with unopened bottles containing oxidized -shot- (characterized by thick, black concentrates) chemistry - and *most* have been of the "single concentrate" variety.

    I do know that the instructions I've read all give different keeping properties for mixed/diluted vs. unmixed/undiluted storage.
    True - the concentrates will last *much* longer than working solutions.

    BTW - Paterson and Tetenal BOTH produce "multiple component" chemistry.
    Carpe erratum!!

    Ed Sukach, FFP.

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    Ed Sukach's Avatar
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    Quote Originally Posted by Chan Tran
    For many years I used Kodak RA-4 and I found that they are pretty harmless. I recently tried some Tetenal and found that their blix is a bit more caustic.
    Interesting!!!

    How did you arrive at that conclusion?
    Carpe erratum!!

    Ed Sukach, FFP.

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    You may call me stupid but I got them on my hands at times. I never felt anything with the Kodak but the Tetenal it did irritate me.



 

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