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  1. #11
    donbga's Avatar
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    Quote Originally Posted by fhovie
    I would prefer to mix up fresh each time - 20ml gives me enough to screw one or two up - I will try these and see - I sure appreciate the help - Thanks all!
    There is really no need to mix fresh solutions each time you print. Both A & B parts will stay "fresh" in the bottle. You will need to put some perservative in the part A jug to retard mold. I mix 1 liter of A and B at a time.

    When you coat use 2 parts A to 1 part B. Works every time.

    Don Bryant

  2. #12
    Gustavo_Castilla's Avatar
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    Try Using baking soda about 1 tsp for 2 quarts of water ( it will do about 3 prints)
    Gustavo Castilla
    We are not moved by things ,
    but by the views we take of them.
    Epictitus.
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  3. #13
    John_Brewer's Avatar
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    Quote Originally Posted by Mateo

    Is it possible that you're losing high value density in the wash?
    That's what it sounds like to me. The negative you want to use for a cyanotype - what grade of normal silver gelatine paper will it print on reasonably well? What are you using for your UV lightsource and for how long an exposure?

    J
    ~John~
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    www.johnbrewerphotography.com
    There are 10 types of people in this world - those who understand binary and those who don't.

  4. #14

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    Yes, you're probably getting high contrast because most of the image washes off in water. To retain the exposed highlights, you need a strongly acidic first bath. Mike Ware recommends a bath of 1% concentrated mineral acid. Not wanting to mess with concentrated acid I use a tablespoon of citric acid in 1.5 l water. Too lower paper contrast further (by increasing maximum density) add 1/4 tsp ferricyanide to the bath.

    Without the first bath I would need negatives with a density range of 1.1 to print cyanotype. With the first bath, I use negatives of about 1.8.

  5. #15
    Donald Qualls's Avatar
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    FWIW relative to the ferric ammonium citrate solution -- I've got a couple half-liter jars of it (dark glass with tight, black plastic lids) that are just over a year old, and there's no trace of mold in the one that's been opened several times for use. I did mix the stuff originally with distilled water instead of tap water, that might make a considerable difference (no spores in the water to begin with).
    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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