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  1. #21

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    Quote Originally Posted by castilg
    Not bad what paper did you used? and exposure time?
    This is Crane's Kid Finish, at about 4.5 minutes in slightly hazy sunshine exposing through 5x7 FP4+.

  2. #22

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    Quote Originally Posted by Donald Qualls
    This is what I'd expect with an alkaline water supply. Acidifying the wash water as you've done is the simple way around it. Unfortunately, cyano requires too much water to use distilled for the development/wash, at least if you have to buy your distilled water -- if you have a distiller, it might be practical to wash in distilled.
    The acid prevents density loss, but it doesn't prevent bleeding. I wonder if there's some other difference between our processes. What paper do you use?


    Now *that* is a neat trick. I suspect, however, that it's equivalent to peroxide treatment -- that is, it's just oxidizing the Prussian blue to its maximum density. Have you tried the bath in very dilute hydrogen peroxide as a comparison with your ferricyanide additive?
    The effect is quite different from peroxide and aerial oxidation. It gives a much deeper tone. It's possible that it's the equivalent of increasing the amount of ferricyanide in the sensitizer.

    It's almost TOO good - my girlfriend looked at it and said it doesn't even look like cyanotype anymore. It looks almost like someone loaded an inkjet with very deep fountain-pen ink. If only I could curb the bleeding.

  3. #23
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    The paper I've used is what was cheap at Fred Meyer (a local everything store when I lived in Seattle area): ProArt (made in Malaysia, company address at a PO Box in Beaverton, OR, a suburb of Portland), acid free, 140# (300 gsm) natural white cold pressed. It appears to be fiber reinforced (it doesn't wrinkle when wet) and came in a wire-bound book of 15 sheets, 7x10 inches. I've been getting as many as four 9x12 cm prints from a sheet.

    My chemistry is the Formulary Traditional Cyanotype dry chemical kit; I haven't ever used the arrowroot starch sizing, but simply coat the paper directly. I have sometimes used one drop of the 2% potassium dichromate solution in 2 ml of mixed sensitizer, but mostly I get better results without it. And I haven't attempted a print in several months; since moving to North Carolina last fall, I haven't even opened the chemical bottles to see if the ferric ammonium citrate has gotten moldy.

    It's very possible the ferricyanide in the first wash is acting like more ferri in the sensitizer, but it might also be reacting with unexposed sensitizer and causing or contributing to your bleeding. Seems to me there was a ferricyanide based "ink'" formula as one of the experiments in the chemistry set I had when I was in about 5th grade. I seem to recall that increasing the proportion of ferri in the original sensitizer would tend to make the print faster, which could cause fog you'd see as bleeding.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  4. #24

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    I get bleeding with or without ferricyanide in the bath. Its main negative effect is that the highlights don't clear as well.

    The ink experiment in your chemistry is probably Prussian Blue, same as the cyanotype! It's used as fountain-pen ink etc.

  5. #25

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    Resurrecting this thread because I think I've figured out the mechanism of the bleeding. The mystery to me was always why there was no bleeding visible after washing - it always showed up during drying. I thought this was because invisible Prussian white, bled out during washing, became oxidized into Prussian blue during drying. It turns out that it's actually Prussian blue diffusing through the paper during drying!

    I found this out by bleaching out the bleeding around the edges of the print. When I washed the print and laid it to dry, more bleeding appeared.

    Obviously, drying the paper faster might help. Does anyone dry their cyanotypes with a blow dryer or oven?

    I'm using Crane's Kid Finish and Crane's 90lb cover.

  6. #26
    Donald Qualls's Avatar
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    I've always dried mine with a blow drier. The fiber reinforced watercolor paper I'm using doesn't curl (much) or wrinkle, and the prints are dry in a minute or two with the drier on low.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  7. #27

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    Thanks! And you say you get no bleeding, right?

  8. #28
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    Correct, though the last time I printed most of my image washed off -- I'm told that was because I underexposed the print, after several months away. I plan to try some more, if I get time before the weather gets cloudy again.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

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