Conservation of drawings for Octavio Medellin’s Saint Bernard of Clairvaux Catholic Church murals

On the Hamon blog in March, Ellen Buie Niewyk discussed the history of Octavio Medellin’s murals for the the Saint Bernard of Clairvaux Church in Dallas and the drawings held in Bywaters Special Collections. Medellin donated these drawings to Bywaters Special Collections in 1996 where these drawings have been rolled in storage for many years. Niewyk contacted  paper conservator Cheryl Carrabba to carefully unroll and repair these drawings. Carrabba, who lives in Austin, works as a conservator for museums, libraries, archives and other institutions. In this post, she details decisions she made in her conservation and her intricate process to restore them.


The Octavio Medellin project included twelve mural sketches for his “Stations of the Cross” mosaic in the St. Bernard of Clairvaux Catholic Church in Dallas. Four of the sketches are executed in colored pencil on medium weight, white paper. Eight are graphite on thin, lightweight, wood-based paper.

All of the drawings arrived in the lab rolled in brown paper backing sheets. Their condition indicated they were exposed directly to standing water, causing damage to all twelve sheets. In addition to pigment bleeding, severe discoloration, and hard water staining, the paper exhibited creasing, fold overs, and losses to corners bearing image details. Disfiguring tears and insect soiling were also present. Image visibility was compromised. The reverse of all these drawings were stained and mottled with animal glue deposits. Inherent aging had caused adhesives to bind the image-bearing sheets to the backing sheets.


OM.96.22: Stations 12 and 13, “Jesus dies on the cross” and “Jesus is taken down from the cross.” Note the losses and dark stain on the left edge in the first image. The sheet was also significantly curled. The second image shows the fills with original blank backing paper, stain reduction, and lining.

After photography and documentation, all surface debris was removed using rubber erasers and soot sponges in preparation for washing. The paper was flattened and cleaned with absorbent blotters and salt solutions consisting of calcium, ammonium, and sodium. These chemicals swell the papers and help release the residue caused by prolonged dampness in storage. After the surface debris was removed, multiple applications of calcium hydroxide, ammonium dibasic, and sodium borohydride were carefully applied to diminish tidelines or pooling of liquid. Tears were delicately mended with sheer-toned Japanese paper and wheat starch paste.

OM.96.23: Station 14, “Jesus is placed in the tomb.” Here water damage is seen not in one dark stain, but as vertical lines of discoloration on the left half of the sheet and glue staining across the top and bottom. Losses and tears are also present. Fills, mends, stain reduction, and lining is shown in the second image.

The graphite sketches were lined using two layers of Japanese paper: Yamakozo Hidura and Tenjugo. Linings were attached to the reverse of the sheets with wheat starch paste using a polyester cloth pasted to a Formica table surface in a tension drying method. The result of this process can be seen in the featured image. Because the colored drawings are on a stronger weight paper made from a mixed blend of cotton and wood fiber, they did not require lining. To fill losses at the edges, we used the original blank backing paper. This mend assured that the fills were the same weight, tone, and fiber as the drawings themselves.

OM.96.12: Station 1, “Pilate condemns Jesus to die.” The paper bearing the colored pencil sketches is heavier-weight and a mixture of cotton and wood pulp, so it did not suffer the same level of deterioration as the graphite drawings and did not need to be lined. Mends and stain reduction were performed.

The conservation process not only improved the appearance of the Medellin sketches, but raised the pH of the paper to alkaline, promoting longevity. This step is especially important for wood-based papers. Together with archival framing methods, storage, and high resolution scanning, the art is preserved to ensure future stability.


Feature image: Example of tension drying method. Polyester cloth is adhered to the Formica table surface, on which Japanese paper is pasted underneath the drawings. This method flattens the sheets and allows the lining to be attached to the reverse.

Blog post: Courtesy of Cheryl Carrabba, Senior Conservator at Carrabba Conservation
Image credits: Cheryl Carrabba

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