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  1. #11

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    Ok, I give up. The clearing problem worked out, but the sensitizer keeps deteriorating. Every time I use it its contrast has declined. I add dichromate to counteract that, but I can't keep up. Right now it needs a neg contrast range of 2.5. I think I'll try Bostick & Sullivan's "improved" two-solution formula instead.

  2. #12

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    For you other cyanotypists out there: I first tried the traditional sensitizer with only ferric ammonium citrate and potassium ferricyanide, but found the shadows bled into the highlights despite an acid first clearing bath.

    I then added oxalic acid and ammonium dichromate as per the formula on Bostick & Sullivan's site (it's also cited in Mike Ware's book). It has no bleeding and seems satisfactory in all respects. My one problem now is that I get some solarization of the shadows when I overexpose, but I'll simply have to avoid doing that.

  3. #13

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    Quote Originally Posted by psvensson

    Bostick & Sullivan shipped the ferric ammonium oxalate in a white plastic bottle that obviously lets through light. That doesn't seem like a good idea. According to Ware, the solid salt is sensitive down to green light. I've written to B&S about that, but haven't heard back yet.
    Let me know waht you hear on this. I bought a bottle and am awaiting my scale.

  4. #14
    Gustavo_Castilla's Avatar
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    is this the same as Photographers' Formulary FORMULARY LIQUID CYANOTYPE 07-0091
    if so I love the stuff
    Gustavo Castilla
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  5. #15
    Donald Qualls's Avatar
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    The "Ware's" Cyanotype is what Formulary calls the "New Cyanotype" -- the kit has about 1/10 the material at the same price as the "Traditional Cyanotype" kit. The difference is said to be cleaner whites, much higher sensitivity, and a single solution rather than needing to be mixed immediately before sensitizing. I'm not at all sure it's worth 10x the price, but I'm on a budget...
    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.

  6. #16

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    Sorry, I have to correct my previous post: adding oxalic acid to the "traditional" solutions does nothing for me. I still get the bleeding. It's not visible when the print is wet, but once it's dried it shows. I can only surmise that it's the insoluble Prussian white that gets shaken loose in the acid bath and spreads through the paper. It doesn't happen when I skip the acid bath and wash the print in running water, but that takes most of the image with it as well. I'm going to try putting the exposed print in a film tank with acidified water, then agitating vigorously. If that doesn't work I'm on to other processes..

    According to their tech sheet, Photo Formulary's Liquid Cyanotype is the traditional formula, sans oxalic acid. Hm... looking at their tech sheet, I see they say a first wash with a little potassium ferricyanide will increase contrast, but it doesn't say if that's because it will clear the whites or deepen the blues. Maybe that's worth a shot too.

  7. #17
    Donald Qualls's Avatar
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    My (very limited) experience printing in cyano is that I need to overprint a bit to compensate for the loss in development, but I don't find I lose a large amount of density due to "washing out" unless I hold the print in one place under the faucet. If I use running water in a tray, I can wash out the yellow unexposed sensitizer without much loss of density at all, mostly compensated by the deepening of the blue as Prussian White from overprinting converts back to Prussian blue.

    I've never used an acid bath of any kind, or added oxalic acid to the chemicals, and I haven't seen anything I'd call "bleeding".
    Attached Thumbnails Attached Thumbnails cyano2.jpg  
    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.

  8. #18

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    I've run more tests, and it's pretty clear that my water causes massive loss of density unless acidified. It might have to do with differences in our water supplies.

    I still haven't managed to get rid of the bleeding, but I just realized that adding just a little bit, like half a teaspoon, of potassium ferricyanide to the first clearing bath (along with 1 tbsp citric acid for 1.5l water) deepens the D-max tremendously. It's the kind of blue that you have to look twice at to make sure it isn't black. It also makes the paper almost more contrasty than enlarging paper.

  9. #19
    Gustavo_Castilla's Avatar
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    Not bad what paper did you used? and exposure time?
    Gustavo Castilla
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  10. #20
    Donald Qualls's Avatar
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    Quote Originally Posted by psvensson
    I've run more tests, and it's pretty clear that my water causes massive loss of density unless acidified. It might have to do with differences in our water supplies.
    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.

    I just realized that adding just a little bit, like half a teaspoon, of potassium ferricyanide to the first clearing bath (along with 1 tbsp citric acid for 1.5l water) deepens the D-max tremendously. It's the kind of blue that you have to look twice at to make sure it isn't black. It also makes the paper almost more contrasty than enlarging paper.
    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?
    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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