I have been away from the group and alternative photography for a while. I am now geting back into the Van Dyke process. After some experimentation and reading the various bits of advice from this group, I have settled on Fabriano Artistico paper and two coats of sensitizer. This seems to produce satisfactory results. But I am now in a quandary.
Recently, I note that both Loris and Joe recommend the use of Citric Acid in the initial rinse bath. However, following Peter Marshall's link to a Cyanotype website (http://photography.about.com/library/weekly/aa061801d.htm) I came across the following statement :
"Since Prussian Blue is unstable in alkali, it is essential to keep the water used to 'develop' the cyanotype at least slightly acid. As most tap water is slightly alkaline, and you should add a few millilitres of dilute hydrochloric acid (still sold in some hardware stores as 'muriatic acid') to a bucketful to use. Other acids such as nitric acid can also be used, but it is best to avoid oxidisable organic acids such as citric or tartaric acid, which can later break down the image."
Does anyone know if the same advice re citric acid applies to Van Dyke ?
Bob Redman (UK)
Received on Wed Apr 12 09:34:46 2006
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