[alt-photo] Re: coffee and cyanotype

[Loris Medici]

Francesco, the "bringing down the paper base significantly" issue doesn't
reflect my past experience with tannic acid at all. Yes, there would be a
slight veiling or warming (when compared to unprocessed paper, *side by
side*) of the paper base, but to me it' was far from being significant. My
workflow was: expose, wash / rinse (a couple of changes), clear in mild
citric acid (1-2%), wash / rinse again, bleach in mild sodium carbonate (a
dessert spoon into 2000ml), tone for 3-5 minutes in weak tannic acid (a
dessert spoon into 2000ml), wash / rinse again. Depends on the sizing
strenght of the paper; hard sized papers such as COT 320 are quite resistant
to staining by tannic acid.

Regards,
Loris.


-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Francesco Fragomeni
Sent: 13 Ocak 2012 Cuma 16:18
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: coffee and cyanotype

Toning in coffee is indeed different then tea toning or pure tannic acid
toning. There are a number of different components in coffee which act
differently on the paper and iron in a cyanotype. Depending on the coffee
and duration of toning time, coffee toning can actually yield a more grey to
black tonality with less stain to the paper base then can be achieved with
tea toning and tannic acid which are notorious for bringing down the paper
base significantly.

-Francesco