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  1. #1

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    Van Dyke Brown prints with too much flat blacks...

    Hi,

    after having found the way to do an almost perfect cyanotype (blueprint is ok - I'm going to experiment with toning now), I also started making VDB prints.

    I'm using PDN system to calibrate my R2400 Epson printer and my UV exposure unit. I use Canson transparencies as negatives. Well... after many test prints, I have now a satisfactory color table scale... The problem is the pure black. It is not deep, no matter for how long I set the exposure. To make easier for you to understand, put on your monitor a 0,0,0 RGB square near a 40,40,40 gray block. The brownish black in my finished prints is even lighter...

    I normally expose my VDB for 6'. Have tried different papers. I always expose papers when they're bone dry (I dry them with an hairdryer at cool setting)

    What it could be? Developing perhaps?

    I develop my prints this way

    1) 90" bath in water acidified with winegar (ph <7)
    2) 30" in 3% sodium iposolphyte fixer
    3) 30" in water acidified with acetic acid (stop bath)
    4) 90" in 1% sodium sulphyte (hypo-clearing bath)
    5) wash for 25'

    prolonged or reduced fixing bath won't accomplish better results...

    I don't think there's something wrong in the PDN digital calibrated negative... Even with a Stouffer exposure scale or a paper exposed without any negative on it the black will remain the same.

    I'm going literally nuts...
    Last edited by Fulvio; 10-06-2005 at 01:51 PM. Click to view previous post history.

  2. #2
    glbeas's Avatar
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    Have you tried double coating the paper?
    Gary Beasley

  3. #3

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    Quote Originally Posted by glbeas
    Have you tried double coating the paper?

    sorry, forgot to mention: I always double coat the paper

  4. #4

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    This is the recipe I'm using:

    A) Ferric ammonium citrate (III) 30%
    B) Tartaric acid 5%
    C) Silver nitrate 12%

    mixed B --> A, then added C to A+B

  5. #5
    glbeas's Avatar
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    Gotta check the strength of your chemicals then. Good luck!
    Gary Beasley

  6. #6

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    Quote Originally Posted by glbeas
    Gotta check the strength of your chemicals then. Good luck!

    What do you mean?

    Is there any VDB intensifier? e.g. potassium dichromate?

  7. #7
    Ole
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    Gold toning is a good way to strengthen blacks, as well as making the print tone more neutral.
    -- Ole Tjugen, Luddite Elitist
    Norway

  8. #8
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    okay... Ive done a fair share of VDB printing.
    no matter what Ive personally done true black will never be true black. I always get deep dark chocolate brown as the deepest shadow... although its partly why I love the printing method.
    Ive toned in Gold, selenium, platinum, and palladium. each having a very discernably different look and feel. all of which I liked (except the selenium it just never seemed to work). The platinum really seemed to have the nicest shadow areas in the prints I did.
    now one thing I did find was that I got the nicest shadows on thinner paper.... the thicker paper seemed to not have as strong the the darkness in the shadows.

  9. #9

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    The three things that come quickest to my mind are.

    1. Wrong paper. Many papers are not capable to giving good Dmax with the iron processes. Soaking for a few seconds in a weak acid bath before coating helps with some papers.

    2. Sensitizer. You may have mixed it wrong, or some of the chemicals may be bad.

    3. Humidity. Vandyke, like other iron processes, gives better Dmax in high humidity workding conditions than in low humidity conditions.

    Any of these things could be the problem, but I suspect most #1.

    Sandy
    Quote Originally Posted by Fulvio
    Hi,

    after having found the way to do an almost perfect cyanotype (blueprint is ok - I'm going to experiment with toning now), I also started making VDB prints.

    I'm using PDN system to calibrate my R2400 Epson printer and my UV exposure unit. I use Canson transparencies as negatives. Well... after many test prints, I have now a satisfactory color table scale... The problem is the pure black. It is not deep, no matter for how long I set the exposure. To make easier for you to understand, put on your monitor a 0,0,0 RGB square near a 40,40,40 gray block. The brownish black in my finished prints is even lighter...

    I normally expose my VDB for 6'. Have tried different papers. I always expose papers when they're bone dry (I dry them with an hairdryer at cool setting)

    What it could be? Developing perhaps?

    I develop my prints this way

    1) 90" bath in water acidified with winegar (ph <7)
    2) 30" in 3% sodium iposolphyte fixer
    3) 30" in water acidified with acetic acid (stop bath)
    4) 90" in 1% sodium sulphyte (hypo-clearing bath)
    5) wash for 25'

    prolonged or reduced fixing bath won't accomplish better results...

    I don't think there's something wrong in the PDN digital calibrated negative... Even with a Stouffer exposure scale or a paper exposed without any negative on it the black will remain the same.

    I'm going literally nuts...

  10. #10

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    Quote Originally Posted by scootermm
    Ive toned in Gold, selenium, platinum, and palladium. each having a very discernably different look and feel. all of which I liked (except the selenium it just never seemed to work).
    Kodak Selenium Toner contains sodium thyosulfphite... It is a fixer and tends to lighten the print. If you soak an overexposed print in a selenium bath diluted 1:40-1:60 the result can be pleasant. Normally the bath doesn't take longer than 15-20". I'm unconfortable with selenium because of its toxicity. I prefer to use strong toxic stuff unless is strictly necessary to the process itself.


    now one thing I did find was that I got the nicest shadows on thinner paper....
    the thicker paper seemed to not have as strong the the darkness in the shadows.
    I was thinking about the same... But that won't explain why the Arches Platine is reccomanded while it should be 300gsm, a relatively heavy paper!

    Anyone obtained more success sizing the paper with gelatin or cornstarch?

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