Making the Invisible Visible: Conservation and Islamic Art

April 2–August 4, 2013

Case Study: Tile Panel from Syria

Sarah McGregor
Associate Conservator
The Sherman Fairchild Center for Objects Conservation

Fig. 1. Tile Panel, ca. 1430. Syria, Damascus. The Metropolitan Museum of Art, New York, Gift of Professor Maan Z. Madina and Dr. Marilyn Jenkins-Madina, 2009 (2009.59.2a–p)

Conservators, curators, and museum preparators often work together to devise creative solutions for the safe and aesthetically pleasing display of fragmentary objects. This collaboration was critical to the successful treatment and mounting of a large panel of tiles from Syria dating to the fifteenth century. This panel, measuring approximately four square feet, originally consisted of twenty-five tiles, of which the Museum has eighteen (fig. 1). These tiles, which would have adorned the interior of a building, were made using stonepaste, a composite of crushed quartz, glass frit, and white clay that was pressed into a frame to obtain equally sized tiles. The raised molding found on the tiles was shaped separately by hand and attached to the surface using a clay slip (fig. 2).

Fig. 2. Above: The break edge of a tile fragment, showing the thin, horizontal line between the molding and the base where the molding was not sufficiently bonded to the base; Below: The side break edge of a tile fragment that is stained from the animal glue that was used in a previous restoration. The unglazed surface can be seen on the top of this tile, where the molding had once been attached with slip. Raised molding is often vulnerable to loss, especially if the slip has not bonded the molding to the base sufficiently.

A grid of incised lines, which can still be seen within the octofoil in the center of the panel, was laid out as a guide for painting after the initial bisque-firing (fig. 3). The black outlines of the floral and the geometric designs were then painted, followed by the cobalt blue and turquoise glazes, all of which were coated with a transparent glaze before refiring.

Fig. 3. The yellow arrows point to the incised lines that were made in the stoneware before the tile was glazed and fired.

The tiles had suffered varying degrees of damage over the years, as well as poorly executed restorations that had become discolored with time (fig. 4). Many of the tiles had chipped or missing corners and some had sections of the missing molding that had been replaced with plaster and/or ceramic molding taken from similar tiles. After a complete examination, it was decided to remove all previous restorations. In a few cases, the extraneous molding fragments were re-adhered after removal and cleaning if their shape and size closely matched what was lost. Otherwise, the extraneous fragments were removed, labeled, and returned to the Department of Islamic Art for separate storage.

Fig. 4. One of the tiles before treatment

New plaster fills were made separately and adhered in place using a stable and reversible acrylic resin. All fills were painted to match surrounding decoration as closely as possible (fig. 5)

Fig. 5. The same tile from fig. 4, after treatment.

After all the tiles had been treated, one question remained: how to display this fragmentary tile panel in such a way that visitors could appreciate its original visual impact. It was agreed that the missing areas should be represented by a drawing on the backing board, to which the tiles would be mounted. Brian Cha, from the Museum's Graphic Design Department, took careful measurements and created digital images of the tiles. Using a CAD (computer-aided design) program, he produced a full-scale drawing on which the existing tiles were placed to obtain a correct alignment between the drawing and the tiles. Once adjustments were made, a large sheet of tracing paper was placed over the drawing and the missing areas of the design were traced by hand. The tracing was then scanned and converted into a form that would allow it to be silkscreened onto a lightweight but strong honeycombed panel.

The next step was to mount the tiles securely to the panel with the faces and edges of the tiles flush and tightly together.

Fig. 6. Fred Sager, Senior Preparator

Being hand made, the tile backs are not perfectly flat, and slight variations in thickness exist. The original craftsmen had a yielding bed of mortar to accommodate these inherent variations. Working without mortar, Fred Sager, our Senior Museum Preparator, mounted the tiles by custom designing brass clips for each tile (fig. 6). In several areas, brass washers were stacked onto the clips to fill gaps between the tile back and the honeycomb board (fig. 7). All of this work took place over a sheet of clear Mylar to prevent any scratching to the silkscreened drawing. After all of the clips had been made, the Mylar sheet was removed, the clips were attached to the panel with screws, and the tiles were gently slid into place. The visible parts of the clips then were painted with acrylic emulsion to match the adjacent tile surfaces.

Fig. 7. Side view of the tile panel. The white arrow points to a clip that has a stack of brass washers supporting the unevenness of the back of the tile.

Additional Reading

Keblow Bernsted, Anne-Marie. Early Islamic Pottery Materials & Techniques, Archetype Publications, 2003.

Degeorge, George and Yves Porter. The Art of the Islamic Tile, 2002. Published originally as L'art de la ceramique dans l'architecture musulmane by the same authors in 2001 by Flammarion.