From: Ed Buffaloe (EdBuffaloe@UnblinkingEye.Com)
Date: 12/07/02-05:31:52 PM Z
Wynn White writes in his article on VDB: "Most sources state that Vandyke
prints can be cleared in plain water. In Mike Ware's description of the the
argyrotype process (http://www.mikeware.demon.co.uk/argy.html) he explains
the problems iron-based silver processes have. If processed in an alkaline
solution residual ferric iron is left in the print which will eventually
cause it to fade since iron (III) will oxidize silver. After reading this I
decided to change my personal clearing procedure. Since my tap water is
quite alkaline at a pH of about 8 I feel that there is a danger of insoluble
iron being left in the print after a conventional wash. To avoid this
problem rather than use running tap water to clear Vandykes I run them
through a series trays that have been filled with water to which I have
added a pinch of citric acid so that the pH falls just below 7."
I have always followed Wynn's advice and have never had problems with
fogging of my VDB's.
----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, December 07, 2002 3:14 PM
Subject: RE: VDB test results: related concerns
>
> I have a further concern about VDB that results from the processing
> of very large prints. When I make such prints my practice is to make
> them in the darkroom but for reasons of space wash them outside. The
> washing usually takes place in the afternoons when the sun is still
> up, in the shade on the deck. Even after processing that includes
> toning, two separate fixing baths, and a final bath of 1% sodium
> sulfite, VDB prints will develop very noticeable fogging when the
> wash takes place outside, even in very low light. I am wondering if
> in spite of all of the processing care there are not still some
> soluble salts left in the paper? If so this suggests the need for a
> very long wash, even if using hypo clear or sodium sulfite clearing
> baths. I thought at first that the fogging might be due to something
> else in the paper other than silver salts but the fogging only takes
> place in the areas that have been brushed with the sensitizer.
>
> BTW, the fogging does not take place with kallitype processed
> following the same procedures.
>
> Sandy King
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