RE: Van Dyke Contrast

Philippe MOROUX (Philippe_Moroux@msn.com)
Fri, 21 Jun 96 19:43:06 UT

I really do *insist* on the *no more than 20 seconds first wash*, performed
with agitation in a distilled water + wetting agent bath.
There would probably be a risk if your water is too alkaline (Hello Terry with
the deep blue cyanotypes).
Also presence of chloride ions in this water is supposed to create unsoluble
silver chloride which will be far more annoying than iron stain, they will
probably need more than 5 minutes fix in a 2% hypo bath to disappear (it is
watercolor paper, isn't it?).

Some of my 5 years old VDB, which have been exposed in a gallery during 2
months in full June sunlight, only show a little drawback (less reddish).

The iron of VDB seems to be more soluble than the one of kallitype. Where is
the chemist?

L'eau ferrugineuse, quelle eau ferrugineuse?

Philippe

. philippe moroux (http://www.knoware.nl/users/philippe/)
... r. van goensstraat 71, 2593 EG - den haag / nl
... tel: +31 (70) 347 86 13 - fax: +31 (76) 525 03 05
. email: philippe_moroux@msn.com /or/ philippe@knoware.nl

Judy wrote:
>
>Also, I *strongly* advise against giving only a 20-second first rinse as
>someone has suggested. As I understand VDB, this would risk leaving
>residual iron, which would degrade your print sooner or later (probably
>sooner).