Brownprints

I think it would be important to clarify whether or not the prints
you are speaking of are in fact Vandyke prints. Are these prints
negative or positive images? If negative, white lines on a brown
ground, then they are most likely negative Vandyke prints. There are
other factors, such as the characteristics of the print surface
which can also lead to the identification of Vandyke prints. The
Vandyke process was actually invented in about 1889 with a patent by
a Mr. Vandyke found in 1901, so Vandyke prints from the 1890's may
be found.

If the prints have brown lines on a white ground it is possible that
they could be positive Vandyke prints, brown line diazotypes or
sepia diazo prints. And, if the date is early (from 1861 through
1930), it is possible that you may have faded ferrogallic prints. If
a date of manufacture can be determined this would help in
identification. Vandyke prints were used primarily from the 1890's
through the 1930's whereas sepia diazo prints begin to appear in the
1920's and are still in use today. Again, the characteristics of the
surface: matte, glossy, flat or raised fibers, are important clues
to identifying these prints. Identification cannot be made on the
clue of color, or any one factor, alone.

As for the fumes, if these are Vandykes, they are possibly not well
rinsed and therefore offgassing products in relation to the sodium
thiosulfate fixer (not developer).Vandyke prints are relatively
stable if isolated from other prints, especially diazotypes, which
may contain thiourea which is detrimental to the silver in the
Vandyke print. In my experience, working with a collection of over
200,000 architectural plans, the Vandyke prints, which were found
among the plans housed in folders,  flat files and on wooden
shelves, were not offgassing noticeably and could be viewed under
limited light conditions.

If they are sepia diazo prints, they do not smell like diazotypes,
but may have a very strong odor. A colleague of mine, Judith Reed,
has worked extensively with architectural plans and remembers her
eyes being irritated when she worked with sepia diazo prints for a
long period of time, especially if a large number of them had been
stored together. In my experience, odor is not a reliable clue to
use in identification. What the effects of offgassing may be to a
user I do not know.

In my and my colleagues estimation the best housing for these prints
is to isolate each individual type to avoid risk of deterioration.
Our practice was to use mylar inner folders within large map
folders. If your drawings are rolled then it is best to keep them
rolled with mylar folder segregations unless a large project to
flatten them can be undertaken. The staff at the Frederick Law
Olmsted National Historic Site (NPS) is involved in such a project,
under the direction of Wendy Gogel.

As with many photographic materials, exposure to light can fade
these images. Keep exposure filtered for UV light and limit the
exposure when in use.

At this time I am  completing a manuscript for publication on the
subject of identifying and caring for architectural
photoreproductions (Architectural Photoreproductions: A Manual for
Identification and Care; Eleonore Kissel and Erin Vigneau; Oak Knoll
Books, New Castle, DE). My co-author and I, with Judith Reed,
published a paper on our early research, "Photo-Reproductive
Processes and Related Issues: The Rehousing Project of an
Architectural Drawing Collection", which can be found in the AIC
Book and Paper Group Annual, 1995.

    **** Moderator's comments: This article is available in CoOL.
    <URL:http://palimpsest.stanford.edu/aic/bpg/annual/v14/reed.html>

Erin Vigneau
Assistant General Collections Conservator
Princeton University
Firestone Library
One Washington Road
Princeton, NJ 08544
609-258-2451
Fax:  609-258-4105

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                  Conservation DistList Instance 11:85
                 Distributed: Wednesday, April 22, 1998
                       Message Id: cdl-11-85-001
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