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  1. #21

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    Hi all, hi PE,

    So I tested again the quickly washed FB print with the HT2, a few meter from a 60W incandescent wall light. And again, after 5 minutes, I got no stains, or barely visible one !
    Then, I done the same test using another FB paper (Adox Vario Classic), with a quickly washed print : I got more visible stains, but I have to go under a brighter light to see them without hesitation. I am confused again

    I presume I had storage problem with the HT2 bottle, but I find it rather strange, as there is no visible alteration on the test solution (clear, transparent color).

    Quote Originally Posted by Photo Engineer
    Ok, this is Silver Nitrate in Acetic acid. It tests for retained hypo. It forms a brownish red stain in the presence of hypo and Silver complexes which cannot be seen in red light. The Kodak instructions that I have are not specific to wet or dry. They are vague. They are vague also as to the lighting conditions. I have several sets of documents though so I'll look more.
    I find this vagueness rather surprising considering the subject importance ! Especially after reading the extensive "Washing Film - Best Environmentally Friendly..."thread on the matter.

    Best regards,

    Raphael

  2. #22
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    I have now read 3 Kodak versions, test wet, dry and not specified. So, I guess it does not matter. I get a rather dense test when there is retained silver. So, if there is no color and no precipitate in your test solution it should be good. As noted, it is Silver Nitrate in Acetic Acid. That is all. Little there to spoil unless it was exposed to heavy light.

    PE

  3. #23

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    Silver nitrate is somewhat light sensitive in that it will turn gray with prolonged exposure. This is why it is packaged preferably in brown glass bottles. Silver sulfide is not sensitive to light. If it were then sulfide toning of microfilm for archival storage would be valueless.

    The Kodak test solution is probably better than the Ilford. The reason for the acidification with acetic acid is to prevent silver oxide from forming with any alkali still present in the paper. In the presence of hydroxyl OH- ions silver hydroxide first forms an then quickly decomposes to silver oxide. Silver oxide is brown or black and its presence would distort the test results.
    Last edited by Gerald C Koch; 02-21-2013 at 07:20 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  4. #24

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    back with a vengeance

    Hi PE,

    Quote Originally Posted by Photo Engineer View Post
    I have now read 3 Kodak versions, test wet, dry and not specified. So, I guess it does not matter. I get a rather dense test when there is retained silver. So, if there is no color and no precipitate in your test solution it should be good. As noted, it is Silver Nitrate in Acetic Acid. That is all. Little there to spoil unless it was exposed to heavy light.
    PE
    Conducted a few more test, but under broad fluorescent light.

    I was then able to see that there is in fact a few small cristals or "sand grains" on the bottom of the bottle. Does it mean that I have to discard it ?

    However, with a more generous lighting, I got quickly non-ambiguous stains on the Adox Classic paper I tested. The next stage is to test this way, quickly washed and archival washed print, side to side, to see if there is a significant difference.


    Where I am still puzzled, is that I cannot get any significant stains on the Forte Fortezo paper, whatever lighing I use, and even if I let the HT2 drop more than 15 minutes.

    So, another question I have, maybe a dumb one, is : if the fact that the Forte Fortezo is stated to be a "chloro-bromide" paper can affect the Hypo Estimator testing ???

    Regards,

    Raphael

  5. #25
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    Well, it does sound as if you test solution is going bad. It should be clear of sediment and like water.

    As for test results on different papers, well, they fix at different rates and wash at different rates. RC washes far faster than FB paper. So, at this distance, I don't think I have an answer.

    Sorry.

    PE

  6. #26
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    Quote Originally Posted by Photo Engineer View Post
    As for test results on different papers, well, they fix at different rates and wash at different rates. RC washes far faster than FB paper.
    Archival fixing/washing was a lot harder to achieve with acidic Sodium Thiosulfate based fixers and has gotten a lot faster and easier with modern near neutral rapid fixers. What Raphael considers a "quick wash" might indeed be archival for certain fixer/paper combos.
    Trying to be the best of whatever I am, even if what I am is no good.

  7. #27

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    Hello,

    Rudy, PE, thanks again for your replies.

    I use "modern" thiosulfat ammonium fixer diluted for paper (1+9), and let the print fixes for 2 minutes (for FB papers). The fact that the Fortezo heavy paper, Museum weight (280g/sq. meter !), would be easily washable, is rather counter-intuitive to me ! But I have to make further tests...

    So, on advice of PE, I decided to discard the HT2 solution I made.

    Maybe I will try to make cheeseparing economies here, but is there a mean to salvage the Silver nitrate in solution ? If I dilute the solution with distilled water, and let it evaporate in a crystallizing dish (possibly in darkness, not under the sun !), can I obtain silver nitrat crystals, or it is permanently destroyed by acetic acid ?

    Best regards,

    Raphael

  8. #28
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    Guys;

    FB paper absorbs much more chemistry than RC, and the baryta hangs on to hypo-silver complexes. So, FB wash times should be longer than RC. However, FB wash times vary more from brand to brand due to the larger variations in the nature of the FB material and the baryta coating. There are several sources for these paper supports in Europe.

    PE

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