Re: storing A and B cyanotype solutions

Tom Ferguson (tomf2468@pipeline.com)
Sun, 21 Jun 1998 09:18:57 -0800

Judy Seigel <jseigel@panix.com>
>In my experience (and that of my students) the mold doesn't matter. It's
>not attractive of course, but you can just pluck (or filter) it out, and
>the emulsion works the same as ever. It doesn't seem to return after the
>first crop, or at most the second. Or doesn't in the formula I use,
>which is the fe am cit & potassium ferricyanide alone, without added
>oxalic, or dichromate.
>
>I have remains of two cyanotype formulas on the shelf, my "plain" one has
>no mold re-growth on the A after several years. The one with the oxalic,
>does. <SNIP>

Thge list had a longish conversation about this recently, check the
archives for "Cyanotype Neurosis". I do use the formula with Oxalic Acid,
and I did get continuous mold growth. While I didn't see "problems" in my
prints, it did bother me (thus my "neurosis" subject line). I didn't want
to change my formula, as quite a few prints had already been made in this
series. If I was starting out new, I would try the simpler (no oxalic, no
dichromate) version of cyanotype.

Following others suggestions I first boiled my storage bottles (buying new
ones might have been simpler), and have since kept the "A" solution in my
film (not food) refrigerator in between uses. No mold!

As an interesting aside, I found I got much deeper D-Max tones (on SOME
papers) if I double coated AND avoided heat drying the paper. It is worth
a try!

tomf2468@pipeline.com (Tom Ferguson)