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  1. #1

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    Quercetin Chalcone develops like Pyrogallol

    Patented in 1999, Quercetin Chalcone (QuCh) is sold in health supplement capsules.Capsules of Quercetone contain 250mg QuCh and capsules of Quercenase (which I ordered by mistake) contain 250mg QuCh and 100 mg Bromelain.I doubt the Bromelain in the capsules I used had any effect but cannot be sure,Quercetone would have been better.

    1st QuCh Staining Developer:
    Metol.......................0.2g
    Sodium Metaborate.....5g
    QuCh.......................2.5g (contents of 10 capsules)
    Water to...................1L

    The quercenase was hard to dissolve, I dissolved it with stirring in the Metol +Metaborate dissolved in water at 100C.(Care, unknown hazard).

    HP5 exposed at EI 200 was developed 30min 20C, agitate 10s/min in 1st QuCh.
    A dark brown-yellow stain was produced and there was a relief image in the emulsion.
    Attachments show scans of 0.2 in square sections of HP5 developed in 1st QuCh and in Pyrocat HD, equally sharpened.
    QuCh costs ~$30 for 15g, Pyrogallol costs ~$20 for 100g.
    This post is a spin off from a less specialized thread on Photo.Net:
    http://photo.net/black-and-white-pho...g-forum/00Y1wj
    Thanks for comment.
    Attached Thumbnails Attached Thumbnails 1st Qu Ch.jpg   2011 pyrocat.jpg  

  2. #2

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    Interesting. I've never even heard of this developing agent. I'm confused though - you're comparing it to Pyro but Pyrocat contains Catechol. If it is staining more on the brown side it seems more like Catechol than Pyro, although admittedly the stain color can vary depending on the formulation. In the scans it's hard to compare the two because the first example seems to have significantly higher contrast than the Pyrocat example. It looks quite a bit grainier and sharper, but the higher contrast makes it difficult to draw conclusions.

    Is there any preservative at all in the formula?

  3. #3

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    You never heard of it as a developer because I just found it.
    QuCh is like Pyrogallol because Pyrocatechol forms a complex with Metaborate and will not work with it.

    It took Hutchings years to optimize PMK so dont take my formula seriously, I put it up to illustrate what type of agent QuCh is.

    It may be difficult to make up QuCh as a 2 part developer like PMK Pyro,with a preservative and good activity, eg it seems rather hard to dissolve.

  4. #4

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    Very interesting all the same. Thanks for sharing this.

  5. #5

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    Interesting - it's a flavinoid with polyphenols on it, so no wonder it works as a developer.
    http://en.wikipedia.org/wiki/Quercetin

    I used tannic acid a few years ago and it works as a staining developer as well.
    http://en.wikipedia.org/wiki/Tannic_acid

    My tannic acid developer was similar to yours except I had to use about 5g tannic acid per liter to get good contrast.

    Tannic acid seems to dissolve a bit better than the Quercetin, although there always seems to a bit of lint in the solution from it...
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  6. #6
    MDR
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    Kirk how did your Tannin developer compare to other staining developers and is it possible for you to post the formula ?

    Thanks Dominik

  7. #7

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    http://albumen.conservation-us.org/l...nbeam/toc.html
    In 1864 they knew of Tannic acid, Gallic Acid and Pyrogallic acid developers (CH XIV).
    But in the dry plate Collodion process Tannic acid was only used to preserve the emulsion,Pyrogallic acid was used as a developer (Ch XXXVII).
    So they probabably must have thought Pyrogallic acid was a better developer than Tannic Acid.The reason for thinking this is not clear but it is not encouraging to start a new investigation of Tannic Acid.

  8. #8

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    Plant chemicals that might dissolve in alkaline solution and have not been looked at might include Resveratrol and Ellagic Acid.The molecules are smaller and since have OH groups may form staining developers.

  9. #9

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    My interest in trying tannic acid was from its low toxicity and it's large molecular size. I wondered if it would work more on the surface of the film as I suspected it would not diffuse very quickly into the gelatin, because of the large molecular size.

    I need to find the negs to confirm, but it looks similar in stain to pryocatechol.

    I'm sure the reason they went with pyrogallol rather than tannic acid is the large amount of tannic acid needed in the formulation. Tannic acid is just not as vigorous as pyrogallol.

    I really didn't go more than about 3 tries/reformulations. I'm certain that adjustments could be made formula wise to cut down on the amount of tannic acid needed to get good development.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  10. #10
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    Quote Originally Posted by Alan Johnson View Post
    You never heard of it as a developer because I just found it.
    QuCh is like Pyrogallol because Pyrocatechol forms a complex with Metaborate and will not work with it.

    It took Hutchings years to optimize PMK so dont take my formula seriously, I put it up to illustrate what type of agent QuCh is.

    It may be difficult to make up QuCh as a 2 part developer like PMK Pyro,with a preservative and good activity, eg it seems rather hard to dissolve.
    Alan, I told you about it as a developing agent if you recall.


    It isn't difficult to dissolve, you need to look at other solvents that aren't simply just water. Such as acetone, dimethyl sulphoxide, and ethyl acetate (which you should be able to easily make a mix of with ethanol, which also has some solubility, though not as high as these)
    Last edited by Athiril; 03-10-2012 at 09:17 AM. Click to view previous post history.

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