Throughout the renovation, OMCA’s conservation team has worked with our curators to create display and storage environments that will protect our collections for the future. In addition, conservators have done some intensive work on specific artworks for the Gallery of California Art. This month, Chief Conservator John Burke takes us on a photo tour of repairs to the 1886 pastel Yosemite (Forest Fire in Moonlit Landscape), by Jules Tavernier.

Tavernier painted on thin inexpensive paper that had been attached around its edges to a light muslin “canvas” stretched on a wooden frame. The muslin added support to the fragile paper as he drew with soft pastels (sticks of almost pure pigment held together with a small amount of natural gum). 

As the paper aged, it became brittle, and ultimately suffered two tears. The redwood trunk on the left contained a tear measuring three by one and half inches.

A tear in the night sky measured two inches square.

 The pastel surface is so delicate that the slightest touch can destroy the image. To protect it, conservators could only access the painting from the reverse. Technician Deborah Lohrke designed and built a workstation for the Tavernier that granted access to the back of the painting, while allowing staff to monitor the pastel surface during treatment.

Before attempting a repair, Conservator Peng-Peng Wang tested paper patch techniques on newsprint, a material similar in behavior to that used by Tavernier. Ms. Wang stretched newsprint on a frame and punctured it to create jagged tears.

In order to draw the torn paper together from the backside of the painting, Ms. Wang developed a controlled suction device to gently pull the jagged edges toward her.

She then tested a variety of Japanese papers to determine the best option to patch the tear. The paper had to be thin enough, and the rice-starch paste light enough to avoid creating pucker marks in the paper as it dried. 

Japanese paper and wheat/rice paste are commonly used in paper conservation. Japanese paper, made from mulberry tree fiber, is chosen for its strength, flexibility, and light weight. For this project, we tested Japanese tissues of different thickness with rice paste of various consistencies. “Sekishu Torinoko Gampi” was the best match to the original paper in color, fiber density, and weight. 

The paper repairs must be applied without using pressure, using a mending technique called a “Frankenstein” (so called because of its resemblance to stitches). The technique involves making many paper strips, each about the size of a grain of rice. The paper is torn rather than cut, to create edges soft with fuzzy paper fibers (or “feathered”).  A small amount of paste was applied to one end and a small brush was used to attach that end to just one side of the tear. The next “Frankenstein” was applied right next to the first one on the other side of the tear, creating a zippered effect. Here it is on the actual Tavernier.

After the first side had dried, the final step was to grab the loose ends of the ‘Frankenstein’ and, while pulling the tear closed, attach them to the other side with paste and soft brush pressure.

Satisfied with her experimental results, Ms. Wang began repairs to the Tavernier.  She used a sharp scalpel to cut a small opening in the muslin backing directly behind each tear. Then the tears were laboriously “stitched” closed using the “Frankenstein” technique.

After repairs were completed, any small paper edges that remained visible from the front were inpainted with a small dot of watercolor. Windows in the muslin were sewn closed with a curved needle and cotton thread. The pastel was then reset into its original frame. Compare the before photos (left hand side) with the after photos (right hand side) to see the skill of Ms. Wang’s restoration.

See the final results for yourself! Visit the Gallery of California Art on Level Three and look for Tavernier’s Yosemite in the section of the gallery devoted to California’s favorite national park.   
 

Jules Tavernier, Yosemite (Forest Fire in Moonlit Landscape), 1886, Pastel on paper. Gift of Mary C. Hanchette. All conservation photos: Deborah Lohrke. Gallery photo: Claire F. Meyler.