Conservation Treatment
Senior paper conservator Sylvia Albro tested the adhesive used for attaching the mat and the backings and determined that it was starch-based. She and other staff conservators Heather Wanser, Annlinn Grossman, and Betsy Haude along with conservation fellows Hanako Hirano and Annie Wilker did the conservation treatment of the prints.
First the Conservators separated the prints from their window mats using a variety of methods including Goretex® sandwich humidification, locally applied moisture and methylcellulose poultices. In a few cases the tight fit of the window mat had abraded the surface of the printed ink along the outermost edges, where the papers had been trimmed close to the edge of the image.
Left: Conservator separating backing from music motet print using Goretex® and Teflon spatula. 2007. - Sylvia Albro Center: During Treatment, showing three separate parts: the decorative mat window, the print and the backing. 2007. - Sylvia Albro Right: During Treatment, showing three separate parts: the decorative mat window, the print and the backing, all seen from the verso. Stain and adhesive remain on the original print. 2007. - Sylvia Albro
Conservators removed the print backings using filtered water baths of alkaline pH with calcium hydroxide added. Then the Conservators removed the residual adhesive which remained on the surface of the print paper with an alpha amylase enzyme applied in a buffered solution. To do this they first laid the prints upside-down on Mylar film suspended over a warm bath.
Left: Conservator Sylvia Albro applying enzyme to the verso of a music motet print by J. Sadeler. 2007. - Hanako Hirano Right: Temperature is controlled during enzyme treatment to remove residual adhesive. 2007. - Sylvia Albro
Rinsing the prints several times in an alkaline bath removed discoloration and the residual enzyme. In some cases staining in the paper remained after washing, and so Conservators sun-bleached the prints for several hours in a specially prepared alkaline solution, under a UV filtering Plexiglas®.
Left: Conservation Fellow Hanako Hirano rinsing one of the motet prints after enzyme treatment. 2007. - Sylvia Albro Right: Engravings sun bleaching under UV filtering Plexiglas at the Library of Congress roof terrace. 2007. - Sylvia Albro
Next the Conservators rinsed the prints in a clean bath, re-sized the paper with a 1% gelatin solution brushed on the verso through Hollitex® and then lightly pressed the prints between felts. This treatment greatly improved the appearance of the prints.
Italian 18th century watermark on the backing paper used for one of the music motet prints. 2007. - Hanako Hirano
Conservator Sylvia Albro examined the backings closely after their removal from the prints and found that they were all papers made in Italy from the 18th century. Albro based her analysis on the watermarks present in the backing papers as well as the paper sheet features and the decorative line style of the window covering. The original papers of the prints themselves contained watermarks of Northern European origin. Thus the prints were produced in Northern Europe, but mounted in Italy several centuries later.
Conservators repaired the prints where necessary with Japanese paper and wheat starch paste and minimally inpainted abraded edges, first applying a gelatin isolating layer and next using ground pigments in methylcellulose. Conservators repaired larger losses with toned Japanese paper, but without undertaking any inpainting. They attached thin strips of Japanese paper with the water-torn feathered edges to the sides of the prints using wheat starch paste and attached each print with its false-margins to a new backing board.
Left: After conservation treatment, before mounting. 2007. - Hanako Hirano Right: After the Japanese paper strips are applied to the edges, for mounting in the new mat. 2007. - Hanako Hirano
Conservators then cleaned the original decorative line windows of residual adhesive with methyl cellulose poultices from the verso and light moisture. The decorative windows were drawn in iron gall ink which was very soluble in water; therefore no washing of these windows was possible.
Conservators hinged the decorative windows in place at the top edge over the prints inside the new mat. Because the original dimensions of the Italian decorative windows never fit the prints exactly; the new hinging method enabled them to be positioned over the print and viewed aesthetically in place while not being attached. The mats can be lifted by their hinge to view the entire print if desired.
Left: After completing the mounting of the print. The old mat window is hinged in place and can be lifted to see the edges of the print. 2007. - Hanako Hirano Right: After treatment, with decorative mat in place. 2007. - Hanako Hirano
Conservators made new larger window mats from four-ply acid-free museum mounting board and covered them in blue handmade laid paper from Fabriano, attached with archival mount tissue in a dry mount press. They lined the mats inside with two-ply museum mounting board. The prints are now housed together in a solander box and ready for display and use by researchers in the Library’s Music Division.
