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  1. #21

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    Good to know, has anyone messed around with the new chem yet?

  2. #22

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    Sodium hydroxide (aka caustic soda, lye) is hazardous:
    http://www.ccohs.ca/oshanswers/chemi...hydroxide.html
    But it dissolves Quercetin dihydrate:
    http://www4.mpbio.com/ecom/docs/prod...ebtds2)/152003
    Worth a try as a staining developer, I ordered some Quercetin capsules (you have to avoid those which are not the pure stuff).

  3. #23
    Ian Grant's Avatar
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    Alan, I posted a question about Quecertin on this Forum 5 years ago. I have a jar of Kodak Quecertin, packaged by Kodak Ltd (Harrow) marked as made by Eastman Kodak in the US, it also says "Not for Drug Use". It came from a metallurgy lab (Murex) in Essex that had closed in the late 1980's.

    Ian

  4. #24

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    hard to compare the two from little scans.
    What's about overall contrast, compensating effect, grain, exposure latitude, speed, and so on ?

  5. #25

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    Harold,
    If you refer to Quercetin Chalcone, I never checked it out as it is so expensive compared to Pyrogallol.
    Quercetin may be similar, if it dissolves in sodium hydroxide, which I hope to test out of curiosity.
    Kodak probably knew about similar substances, from Mees & James 3rd Ed p282:
    "Often an inactive compound in highly alkaline solution may be hydrolyzed or partially oxidized and hydroxylated to form a new species fully capable of developing an emulsion"

  6. #26

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    Developer from Quercetin Capsules

    I now tried to make a staining developer starting with Quercetin capsules ,not the more soluble Quercetin Chalcone capsules mentioned above.
    2.5 g Quercetin poured from capsules was added to 4 g Sodium Hydroxide (Lye) in 100 ml water. This did not all dissolve immediately and was left for 7 days in a 100ml sealed glass bottle with occasional shaking.The level of suspended material in the solution gradually fell but it was not all dissolved after 7 days when the clear orange solution was filtered off through cotton wool.It was made up to 1liter and 0.2g Metol and 15 g sodium bicarbonate (Arm & Hammer baking soda) were added.The pH was 9.8 +/- 0.1.
    Pics of Fomapan 400 negatives developed 30min 20C and a positive are attached.

    The working solution was:
    Metol.........................0.2g
    Quercetin ..................2.5g
    Sodium Hydroxide.......4.0g
    Sodium Bicarbonate...15.0g
    Water to.....................1L

    Conclusion:
    It is possible to make a staining developer from Quercetin capsules but at present:
    (1) It is not clear if the development is due to dissolved Quercetin or Quercetin Hydrate formed by reaction with the Lye.
    (2) If there is an easier way of making it up, preferably avoiding hazardous sodium hydroxide (see previous posts).
    Attached Thumbnails Attached Thumbnails Qu stain 1.jpg   Qu 2.jpg  

  7. #27

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    Owing to the low solubility of Quercetin compared to pyrogallol,pyrocatechin and hydroquinone (all in staining developers), it seems not possible to make a water based concentrate of it, and unlike these others, Quercetin cannot be made into a water based stock solution concentrate.I therefore tried a dilute 1-shot solution:

    Metol .................................0.2g
    Quercetin............................2.5g
    Sodium Carbonate anh..........5.0g
    Water to...............................1L

    These were shaken up together in a full sealed glass bottle, after ~24 hrs most of the Quercetin appeared to have dissolved.
    APX 100 was developed 30m 20C.This worked well, giving brown stained negatives.I verified these were also tanned by bleaching in !0% Potassium Ferricyanide and Bromide solution and fixing.
    A relief image formed by tanning was visible.
    That carbonate solution worked indicates the it is likely Quercetin and not some hydroxylated derivative that is the developing agent.

    AFAIK the only commonly used 1 shot solution that is premixed just before use is Caffenol so that is next to test.

  8. #28
    Rudeofus's Avatar
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    Does it need the high pH of Carbonate to get Quercetin into solution? This page claims that Quercetin's first pKa is 6.44, which tells me that much weaker alkalis (Borax, Sulfite) should dissolve it in quantity. There is a good chance you can make a stable stock solution at pH 7.5 that both contains Quercetin in higher amounts and is not overly prone to premature oxidation.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #29

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    Worth a shot, I'm due to mix it up as far as b&w goes. I'll post proofs in a month or so.

  10. #30

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    It is possible to make a borax solution but it is not very concentrated and develops more slowly than the carbonate version.

    Metol.....................0.2g
    Quercetin...............1.0g
    Borax.....................3.0g
    Water to...............100ml

    In a stainless steel container, boil and simmer 5 min,filter through cotton wool (about half the Quercetin dissolves).
    Make up to 100ml ,store in a full sealed bottle.Dilute 1+9 for use.
    Development time is over 30 min.

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