Re: Toned cyanotype query
Thank you for your very helpful reply! I've done a little toning using
washing soda and tannic acid-- but hadn't figured out the general
alkaline/acid relationship. That gives me lots of new things to try! I
don't remember ever hearing of gallic acid, but apparently it's found
in a lot of plants that grow locally, so it should be easy to come by.
One book I have recommends sulphuric acid for purples, but I don't have
any of that laying around the house! My husband has some muriatic acid
and I've been working up the nerve to try that...
On Oct 27, 2007, at 3:03 PM, Christina Z. Anderson wrote:
Nice to see a "newbie" post for once on this quiet weekend!!!
With toning cyanotype it is very easy: you use an alkaline to bleach
the print, and then an acid to "redevelop" or tone. The alkaline can
be TSP, sodium carbonate, ammonia, borax, sodium or potassium
hydroxide, etc. Then the toning part is tannic or gallic acid and
that from tea bags, the actual powdered form of tannic or gallic,
walnuts, other nut hulls, etc. etc.
There are myriad different formulae and recipes to get different
colors from yellow to brown to purple to black to deep blue.
Now, the question you ask is how to get eggplant tones--from my
experience the more purplish tones come with ammonia as the alkaline
and redeveloping in gallic. But that soooo depends, because you can
actually tone first and THEN bleach, bleach partially and tone long,
on and on. And each method has a characteristic color produced that
can only be found by trial.
If you have none of these chemicals except household stuff, try a test
print of a brief ammonia bleach (partial bleach) and then tone in tea
(1 bag per cup water).
This'll get you started. Kai Hamann may still be on the list and he
will give you OODLES of ideas, as are other people, too--Sam Wang,
Judy Siegel, come to mind as having done a fair amount of toning of
cyanotype. Jill Enfield and Christopher James' books have different
colored toner formulae in them. How about googling the Metoyer guy
and asking, too? If you do, report back to the list.