Glass plate negatives

Our Archives has received a small collection of dry plate glass
negatives circa 1940's. The majority of the plates are 16.5 cm in
length by 12 cm wide while a small number are 21.5 cm in length by
16.3 cm wide.

The negatives were stored in their original boxes, some in glassine
envelopes. All negatives present a red coloured pressure sensitive
tape applied around all edges. Some individual plates display a
number of images and in these cases, the tape is also used to
separate the images. Over time, the adhesive has leached, causing
some of the negatives to stick together.

I am wondering how I can safely separate these negatives. Some have
been easily separated mechanically while others will not budge.
Also, should the tape be removed from the negatives and if so, how
can this be done safely? In cases where the adhesive has dried, the
carrier has fallen off, leaving discolouration on the glass. After
removing the plates from their original boxes and glassine
envelopes, I have stored the negatives in four flap folders with the
emulsion side up and have used coroplast as a rigid support.

Audrie Schell
Book and Paper Conservator
McMaster University
Hamilton Ontario
Canada


                                  ***
                  Conservation DistList Instance 20:24
                 Distributed: Friday, November 3, 2006
                       Message Id: cdl-20-24-021
                                  ***