Cyanotype rinsing vs washing
  • Asher, the President of the company, had some nice advice for one of our customers about washing and developing cyanotype. I am going to start posting more stuff like this, which are email questions we get that can be useful for the whole forum. Her question was about how many times should you wash the cyanotype print after it has been exposed.

    " Just to be clear, with the several trays of water (good idea) how much washing do you think should be done? Just until the image is clearly developed? Does active washing/wringing work best or is it also a good option to put the exposed prints into a tray of water and let them sit for a few minutes?"

    Answer:

    "With cyanotype, the first water bath is not a “wash” per se. You can think of this bath more as the “developer” bath. You are “processing” the print, not washing it. During this stage, you are allowing the chemical reaction to occur between the light-sensitive iron salt and the green citrate. A lot that citrate is not used, and washes off the print, thus making the water bath green. You then need another, clean water bath, to “clear” the print of the green. This is more of a “wash” bath.

    Ideally, you would have 4 trays:
    1. One for the initial processing of the print
    2. Another to clear the print and “wash” it clean of the green
    3. A dilute bath of hydrogen peroxide will develop the blue to its deepest color immediately instead of over 24 hours
    4. Another water bath to clear the peroxide.

    That second two baths (3 and 4) are not necessary, but recommended if possible. But I would have at least two water stations. You do not need to wring or work the fabric at all: the prints can just sit in the water."