[Alt-photo] tannic acid

raven erebus ravene at gmail.com
Thu Jun 15 05:32:43 UTC 2017


Different bleaches do change the tone!
If you use baking powder to bleach then green tea you get a rather nice
sepia.
https://www.flickr.com/photos/violentbloom/8671043077/in/album-72157630022024682/

I found that tannic acid didn't work as well as green tea for me.  And
coffee stained the paper more than toning the image.

best,
Raven

On Wed, Jun 14, 2017 at 10:22 AM, Bob Cornelis via Alt-photo-process-list <
alt-photo-process-list at lists.altphotolist.org> wrote:

> 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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