Re: Toned cyanotype query
Whilst there are recipes around which use sulphuric acid as a cyanotype toner, I would be cautious about trying it as strong acids can cause the release of cyanide if there is any residual ferricyanide in the print. I would recommnend sticking to weaker acids such as tannic and gallic.
----- Original Message -----
From: "Linda Stinchfield" <firstname.lastname@example.org>
Sent: Saturday, October 27, 2007 10:44 PM
Subject: Re: Toned cyanotype query
> Hi Chris,
> 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...
> Thanks again,
> Linda S.
> On Oct 27, 2007, at 3:03 PM, Christina Z. Anderson wrote:
>> Hi Linda,
>> 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.
>> 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.
>> Happy Hunting.
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