[Alt-photo] tannic acid

Bob Cornelis bob at colorfolio.com
Wed Jun 14 17:22:23 UTC 2017


Thanks Christina

I am embarking on a "survey" of toning techniques, many of them from your
book! I've done lots of tea toning in the past - I'm not a big fan because
of the heavy staining in the highlights. Recently I've had better success
in that regard with coffee toning. I'm curious if straight tannic acid
gives me more control than tea bags and perhaps less staining.

I've got some other chemistry on its way, like glacial acetic acid and
playing with different bleaches as well.

It's not clear to me in my reading whether different bleaching solutions
give different tones or results at the end of the process, or whether they
all basically do the same thing.

Regards
Bob


On Wed, Jun 14, 2017 at 9:20 AM, Christina Z. Anderson via
Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>
wrote:

> Bob,
> You do not need purified tannic acid to tone cyanotypes. You can tone
> cyanotypes with brewed strong tea as well, e.g. 5 teabags to a couple cups
> of water. You can use green tea. You can use walnut husks. etc. etc. and
> the list goes on. Anything with tannic and gallic acid.
> I have used both the scientific grade tannic (and gallic), which actually
> smells like tea (a very fine powder) and regular tea as have all my
> students for over a decade.
> It doesn’t get used up very fast so if you were to buy scientific grade,
> get a small amount.
> Chris
>
> > On Jun 14, 2017, at 9:48 AM, Bob Cornelis via Alt-photo-process-list <
> alt-photo-process-list at lists.altphotolist.org> wrote:
> >
> > I'm looking for a good, inexpensive source for tannic acid to do
> cyanotype
> > toning. Does it matter greatly whether I buy this from a
> > chemical/photography supply company or some place like the following:
> >
> > http://www.dharmatrading.com/chemicals/tannic-acid.html
> >
> > Much cheaper, but I'm not sure what kind of purity/control I really need
> > for this. Any experience or suggestions?
> >
> > I can get 100gms at Photographers Formulary for about $29, but am looking
> > for something in greater bulk and cheaper.
> >
> > Thanks!
> > Bob
> > _______________________________________________
> > Alt-photo-process-list | altphotolist.org
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