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  1. #1
    John Austin's Avatar
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    Cyanotype printing neg' damage warning

    I don't want this to become a "Dear Marjorie" page about technique, but I will make this exception

    When printing one of Rae's pictures of Mandalay Beach today I discovered that when the negative was last used to print a cyanotype some of the cyanotype emulsion and paper support was transferred to the neg' emulsion. I have tried to wash it away, but the blue stain remains

    The cyanotype paper looked dry, felt dry, sounded dry and said it was dry. However, in a printing frame under the Australian sun it obviously sweated and was not dry enough to avoid damage the original negative

    The lesson here is to firstly make at least two negatives of a good image. OK, waves never repeat, but close can be waited for. Secondly only use copy negatives for alternative processes

    In the morning I shall make a print in the hope the blue gets lost in the paper's blue sensitivity

    Can anyone advise?

    To view this post with pix please visit jbaphoto.com.au

  2. #2
    smieglitz's Avatar
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    Try printing it again first. If it shows enough to ruin the print, then I would try soaking the negative in some alkaline solution... washing soda (sodium carbonate), borax, Dektol, etc., followed by another wash in water. Cyanotypes bleach in alkaline solutions so it might remove the stain. If the Prussian Blue has somehow reacted with the silver of the negative, it might remove part of the image too, but I've never heard of that actually happening. I suppose it would be possible since potassium ferricyanide, a silver bleach, is on of the components of the original cyanotype solution.

  3. #3
    jp498's Avatar
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    Likewise I have a negative that van dyke "emulsion" stuck to the negative because the paper wasn't perfectly dry. I blame it on my hurrying to get from coated to printed. It's not in an important part of the image fortunately. Next time, I just let it dry overnight instead of hurrying it.

    If you have lots of problems like this, perhaps scan before you contact print, then you could make a new digital negative if it's super important.

  4. #4

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    sodium carbonate should bleach out the prussian blue to prussian white. Then it may wash out easier.

  5. #5
    Vaughn's Avatar
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    A thin sheet of mylar or other clear plastic is often used between the negative and the light sensitive material -- to protect the negative from moisture.

    Also try exposing in open shade -- cooler and a bit longer exposure times, and possibly slightly better tonality as the printing out image is allowed to form more fully with slow/long exposures and can give nicer results than with fast intense exposures.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.



 

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