Identifying print

Scott Kellar <skkellar [at] sbcglobal__net> writes

>I have a book with several small maps and illustrations on blue
>paper. The imprint is: Annual Report of Colonel B.H. Grierson, 10th
>Cavalry, Commanding, Department of Arizona, 1889. The maps are on
>white paper, 'cover weight' with a cobalt blue coating on the recto.
>The images and text appear 'etched' and show up as white on the blue
>background, although the white is more of a light blue. The verso is
>white with bluish residue as if coming from the recto. The paper
>does not seem to be brittle.
>
>I would appreciate any insight on the chemical nature of this
>printing process, and how it might be best preserved.

Based in your description, and the period of printing, I guess it
could be Cyanotype. This a photographic process. If so, the image
stability of cyanotypes is good, and severe fading is uncommon.

A cautious recommendation for this prints is to use high-quality
non-buffered papers until the influence of alkaline-buffered
enclosures may cause fading of image.

Clara M. Prieto
Photograph and Art on paper Conservator


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                  Conservation DistList Instance 21:60
                    Distributed: Friday, May 9, 2008
                       Message Id: cdl-21-60-005
                                  ***