Digital BW, The Print

A recent posting in Medium Format Digest led me to a good article on silver
print archival processing at
http://unblinkingeye.com/Articles/Archival/archival.html.

The article makes it clear that even the silver print is still having
trouble with image permanence and, in particular, air pollution. Some of the
information could be useful both directly in helping us make our prints more
archival and indirectly in helping us destroy the myth that the silver print
is in a totally different category than an inkjet print. I'm not suggesting
that I think the toned silver print is not superior, especially with respect
to light fastness, but it is clearly subject to the same air-pollution
problems the inkjet prints face.

Most of the "archival" toned silver prints are not as archival as most
assumed. In addition to the problems of processing, including over-washing,
the real big finding appears to be that the typical selenium toning that
most of us have been doing -- following Ansel Adams' lead -- is not
particularly effective.

To quote the article: "Silver is only protected from oxidation to the extent
that it is replaced or completely plated over by a noble metal (gold,
platinum, selenium, etc.) or a more stable compound. ... The way in which
many fine art photographers use selenium toner, for instance, does not tone
the entire image and therefore does not provide total protection against
pollutants. ... Selenium remains the most popular toner among fine art
photographers. ... Nishimura [RIT] cautions that partial toning or
split-toning with selenium will leave the untoned portion of the print
unprotected, as the selenium preferentially tones finer grains of silver in
high-density areas of the print. Untoned portions of the image may be
subject to future deterioration. This flies in the face of longstanding
advice from Kodak which, as repeated by Ansel Adams and many others, said
that selenium provides protection even in very high dilutions which do not
cause color changes."

Regarding long term stability, "Doug Nishimura of RIT\ufffds Image Permanence
Institute has emphasized repeatedly that image permanence is tied more to
storage conditions than to processing.  No matter how carefully processed an
image is, if it is subjected to atmospheric pollutants it will be liable to
degrade. 'Virtually all of the fading seen in photographs has been caused by
[contaminants in] air and moisture.'"

So, isolation from oxidizers appears to be the key.  The article mentions
the ArtCare board that absorbs many of the harmful oxidizers.  It also notes
that test results indicate that dry-mounted prints, no matter what board
they are mounted on, fare better than prints that are hinged or
corner-mounted. The dry mount tissue serves as a barrier to pollutants that
have been absorbed by the mount board.

Paul
http://www.PaulRoark.com