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Thread: Cyanotype - 10 times faster

  1. #1

    Cyanotype - 10 times faster

    why does nobody use the second cyanotype process, the one hershel used?

    Solution A: 400g ferric ammonium citrate green in 1l of destilled water (store in dark bottle)
    Solution B: 10g potassium ferricyanide in 1l of destilled water

    • Float paper in solution A (or use a brush)
    • dry (dimmed light!)
    • expose about 10 times less than with the original cyanotype formula. You will see a faintly printed image on your paper. The darkest shadows should have the colour of the not-exposed paper.
    • float the paper in solution b (a brush can reduce the resolution of the print)
    • wash until all the yellow is gone.
    • dry (and wait 1h for the full contast.)




    Advantages: it gives me sharper prints 10 times faster
    Disadvatages: you need a lot more chemicals

    try it!
    phil

    p.s. this is where i found it: (in german)
    http://www.swisseduc.ch/chemie/licht_materie/09_cyanotypie_separat/docs/cyanotypie_separat_prakt_lehrerunterlagen.pdf

  2. #2

    Cyanotype - 10 times faster

    Do you have some samples?

  3. #3
    500+ Posts earlj's Avatar
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    Cyanotype - 10 times faster

    Why not immerse the paper in solution b? I don't see the need for the float, if the unused solution washes out. I, too, would like to see some images, especially if you have the same image done with this process along side traditional cyanotype or Mike Ware's new cyanotype.

  4. #4

    Cyanotype - 10 times faster

    @earlj - sorry, i meant immersing (bad english)

    proof of concept from a 30x40cm paper negative (foma 311n, paterson acu, arches aquarelle 21x29cm cold pressed precoated with gelatine/formalin/tween)



    the exposure time was 1h10min. Usually I expose for 12h using the traditional A&B mix.

    full 300dpi scan (7 megs) http://quanttrader.at/img043.jpg

    anyhow, seeing the negative you can guess what is lost on the print. If anybody can tell me how to avoid this - please help ;-)
    http://quanttrader.at/img044s.jpg (scanner too small for full image)


    i brushed this image with solution A 2 times and immersed it in B for development.

    p.

  5. #5
    500+ Posts earlj's Avatar
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    Cyanotype - 10 times faster

    p.:
    You have a pretty nice range of tones in this print. Traditional cyanotype does not display a long contrast range, and you seem to have a negative with a pretty broad range. I don't know what your density range is, but this print looks pretty darn good to me.

    I am going to give this method a try. The extra chemicals is no big deal, as cyanotype chemistry is cheap, and you can re-use the 'developer', can't you?

  6. #6

    Cyanotype - 10 times faster

    earlj,
    to be true I have got no practical knowledge about reusing the chemicals. I would assume that you can reuse the sensitizer. The developer is polluted with a lot of blue and unexposed sensitizer.
    But if you keep it in a dark place...

    I used the developer for several prints and kept it dark in between. Everything was fine.

    But it is my third day with this formula - and I could not find anything on the net about it...

    Let me know how it worked out with your negs!

    p.


    p.s. There is an alternative formula for this process give in Cassell`s cyclopedia of photography (1911) page 68. But it uses uranium nitrate and a much higher concentration of solution B.

    if you search for "the alternative method is to use single solutions" at google books you`ll find the except. (sorry I don`t know how to link directly)

    p.p.s I had some bad experience with hot pressed arches aquarelle paper. It seems that the tonal range of the print depends on how much sensitizer is applied to the paper.

  7. #7

    Cyanotype - 10 times faster

    I too am hard pressed to see the shortcomings in the print. The only shadow dropout is the door way at the bottom, but the mid-tone separation is excellent. I haven't seen many examples like you have here.

  8. #8

    Cyanotype - 10 times faster

    Interesting process and nice print. I'm heading out of town for 2 weeks, so I won't be able to try this this weekend, but I will when I come back. I expose in the sun, and my times usually run around 6 minutes or so. The faster exposure might be just what I need with my UV LED lightbox experiment. The speed of the formula isn't so much an interest for me with sun exposure, but I do like the tonal range.

  9. #9

    Cyanotype - 10 times faster

    Hi Phil.

    Is this method similar to the Cyanotype Rex process? I did try splitting parts A and B a while ago but only brushed on part B to develop and had issues with the brush marking the print. What is the quantity of part B you use for your development bath? Do you use a full litre?

    Best regards,

    Evan

  10. #10

    Cyanotype - 10 times faster

    Hi Evan,

    I have got no idea about the REX process. I never did it...

    You do not need 1l of the solution to start. I tried immersing and brushing, and if you use a hake brush, the outcome is about the same.
    For my tests i setteld with brushing on A and immersing in B.

    If you overexpose the print a lot of collodial blue is build on the print when you immerse it into the developer. If you clean off this collodial blue with a soft shower, an unsharp picture reamins which has not got a nice blue. If you use a brush you get heavy brush strokes.

    phil


    p.s. i am off for 3 days

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