From: Katharine Thayer ^lt;>
Date: 08/10/05-04:08:08 AM Z
Message-id: <>

Judy Seigel wrote:
  I recall that Sil Horowitz,
> chemist, said that there is no risk to archivality from residual
> dichromate, as it's already oxidized (or like that).

Hmm. I know you didn't mean this to be taken as an exact quote, but as
stated here I'm not so sure I agree. I think you must have meant
"already reduced" rather than "already oxidized," but putting that
aside-- when the residual dichromate is yellow as described in the
example below, it's my understanding that the yellow color means that
the chromium is still hexavalent and as such could continue to react
with UV and organic materials in the paper, changing color to brown and
then a darker and darker brown that would certainly alter the appearance
of the print. Whether it would affect the longevity of the paper I
couldn't say.


I remember a series of prints
> done in hot humid NYC summer when I was resisting the air conditioner had
> such an exquisite golden (dichromate) tone over all I tried repeatedly to
> match it with a yellow over-layer.
Received on Wed Aug 10 11:03:39 2005

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