Lion Rampant, a gilded and carved wooden lion, entered the MFA’s American folk art collection in 1960. One of a pair of lions, it had once reared proudly on its hind legs at the top of the Torah ark in the Anshai Poland synagogue in Boston’s South End. The ark and its ornaments are the work of Sam Katz, a prolific woodworker and cabinetmaker who made many of the arks for synagogues in the Boston area in the early twentieth century. Completed in 1923, the ark was later disassembled before demolition of the synagogue in 1957.
Upon examination, conservators noted that the gilded surface of the lion was not only very dirty, but also flaking with some areas of loss. To address these issues, the sculpture needed consolidation (re-adhesion of the lifting gilding), cleaning of the surface dirt, and compensation for the largest area of lost gilding.
First, consolidation of the fragile flaking gilding was necessary to stabilize the gilded surface for succeeding stages of treatment. Conservators chose isinglass, a glue made from the bladders of sturgeon fish, to use as the consolidant because it remains highly flexible even after drying. As an added benefit, when compared to various other consolidants tested, isinglass only slightly darkened the sculpture’s pink bole. (Bole is a ground layer, in this case made of a mix of calcium carbonate and kaolin-type clay, usually found underneath gold leaf.) The isinglass (5% weight/volume in deionized water) was only applied onto the very edges where the gilding met the bole in order to minimize use of the consolidant.
Consolidation was followed by cleaning of the dirty surface. It was not an easy task to choose a cleaning agent because the gilded surface and the bole were both extremely sensitive to a range of water-soluble and oil-soluble solvents. Eventually a two-step cleaning process was devised, first involving an oil-based solvent (Shellsol 340 HT), then a gelled emulsion which managed to extract the embedded surface dirt without removing the original greenish toning applied by the artist. (Toning is often employed to simulate patina on the surface of an object, so that the gilding does not appear overly bright even when the object is newly made.)
The gelled emulsion was also able to remove the disfiguring white bloom that had appeared in the old wax coating. Wax coatings can experience changes to their crystalline structure due to exposure to high humidity or other factors. On the lion, the clear wax coating had changed to opaque white in some spots. These areas of white bloom were successfully addressed with a gelled emulsion consisting of 2% weight/volume tri-ammonium citrate in deionized water, gelled in methylcellulose with several drops of 20% volume/volume propan-2-ol in hexane mixed in.
In the last stage of treatment, a paper fill was prepared for compensation of a lost patch of gilding on the lion’s proper left thigh.
The paper fill was made of three layers of Japanese paper, first adhered together with wheat starch paste, then gilded and toned on the top layer to match the color of the lion.
The paper fill was also molded to the area of loss while the wheat starch paste was not yet dry, since it would be very difficult for flat and stiffened paper to conform to the curves of the sculpture. With the paper fill pre-molded, conservators will then also only need a minimal amount of adhesive to attach and keep the fill in place. Conservation treatments are designed to be reversible, so the less adhesive used the easier to detach should that become necessary.
To ensure the paper fill stayed in position long enough to conform to the contours of the lion’s thigh, a coating of menthol was applied to the surface of the bole. Menthol is a volatile binding media that has seen increased use in conservation, particularly as a temporary consolidant to protect archaeological objects during transport. The advantage of menthol is that it sublimes, passing directly from a waxy solid to vapor without the danger of seeping through the surface as a liquid. On the lion, the menthol eventually sublimed from the surface without leaving any trace.
Once the wheat starch paste had hardened, the paper fill was removed to allow the menthol to completely sublime.
The final steps of treatment, which was suspended due to the temporary closure of the Museum, will involve final toning of the gilded paper and adhesion of the fill onto the lion.