6 CONSERVATION OF BALEEN

6.1 HISTORY OF CONSERVATION TREATMENT

Archaeological baleen has been found in northern Europe, northeastern Canada, and Alaska, and it is likely that other examples exist in regions where baleen was frequently used. A relatively robust material prior to burial, baleen rarely survives burial intact due to its susceptibility to bacterial and fungal growth. Furthermore, several burial conditions, including alkaline and reducing environments, will break down the disulfide linkages as well as the hydrogen bonds. Baleen has nevertheless survived very well in permafrost conditions along coastal Alaska where it is often found saturated with salts and minerals from its burial environment. It is only after the baleen is allowed to thaw and begins to dry that delamination and cracking occur. Historical baleen, on the other hand, is strong and durable but prone to splitting and delamination as a result of dimensional changes caused by fluctuations in relative humidity. Baleen is also subject to attack by insects due to its proteinaceous nature.

The fact that changes in relative humidity can cause dimensional changes in baleen seems inconsistent with Inuit accounts of baleen as a strong, flexible material that is not swelled by water. This inconsistency probably can be explained by the fact that the Inuit and others used it in a fresh, well-soaked state. In arctic climates the constant high relative humidity along the coast would keep the baleen flexible year-round. Such an artifact transferred to an overheated, poorly controlled museum environment would surely desiccate and exhibit splitting and delamination. Baleen artifacts in museum collections today generally are in good condition, but their state of preservation depends on whether the raw material was dyed, worked, or coated and on how it has been stored throughout its lifetime.

The condition of baleen artifacts in museum collections is rarely cited in the conservation literature, although there are some historical precedents for its treatment. In the late 1920s the treatment of baleen aimed at creating a water-resistant coating to help minimize the effects of relative humidity. Two techniques outlined in the Annual Report for the National Museum of Canada in 1929 include (1) soaking baleen in a thin solution of gelatin, allowing it to dry, and then immersing it in formaldehyde and (2) removing a fatty substance found on archaeological baleen and replacing it with a thin immersion coating of a celluloid solution (Leechman 1929). The source does not make clear whether the greasy substance seemed to have been intentionally applied or was just a consequence of burial near fatty substances such as whale blubber.

Between 1978 and 1982, during several field seasons in Labrador, Canada, Mary Peever, formerly of the ethnology lab of the Canadian Conservation Institute, developed a treatment for wet archaeological baleen. Badly delaminated artifacts were immersed in warm water to relax the delaminated sections and consolidated with Rhoplex AC-33, an acrylic emulsion. The pieces were then weighted in place and allowed to dry slowly. Ten years later the artifacts appeared to be in good condition, but Peever now questions the use of Rhoplex AC-33 with a naturally acidic protein because of its alkalinity when wet. Acrysol WS-24, an acrylic colloidal dispersion, has been suggested because of its neutral pH, finer particle size, and higher glass transition temperature (Peever 1989).

In the early 1980s Christine Del Re, of the Field Museum of Natural History, worked on a Native American headdress; the cylindrical frame that fits around the head was made of strips of baleen lashed together with lengths of sinew. The baleen frame was badly distorted, and Del Re describes attempts at humidifying and reshaping the baleen collar as unsuccessful (Del Re 1988). The baleen was placed in a humidity chamber to restore flexibility, a common conservation technique, but water vapor alone was insufficient for such thick plates. In this case, it would have been necessary to soak the baleen in hot water for an extended period to restore flexibility. Because this technique physically and chemically alters the baleen structure, it should not be carried out on original material.

6.2 TREATMENT OF THE SWORD HILT WRAPPINGS

The Japanese swords in the collection of the Walters Art Gallery were treated by two different conservators who approached the problem of replacing the missing and broken baleen with different materials. The brittle baleen strips generally had broken across their widths, and there were many losses. Their poor condition may have been a result of the manufacturing processes or of their subsequent use and storage conditions. In one case, split monofilament nylon fishing line, tinted with Lefranc and Bourgeois restoration colors and adhered with Acryloid B-72 in acetone, was prepared to replace the missing baleen wrappings. Although the monofilament thread made a convincing match for the baleen losses, it was very difficult to work with in small lengths, and it resisted conforming to the curvature of the sword hilt. The other sword was repaired with pared-down strips of vellum painted with Lefranc and Bourgeois colors and dipped in Acryloid B-72 in acetone to build up depth. The tinted strips were attached with methylcellulose in ethanol and weighted until dry. Both swords have been on exhibit since May 1991, and the restorations appear to be holding up very well.

6.3 BALEEN AS A CONSERVATION MATERIAL

Baleen incorporates many desirable properties, such as strength, flexibility, and durability. Consequently, conservators and artisans alike have used baleen for a variety of purposes. Mary Peever reports on a baleen repair on a Northwest Coast mask. Although recently treated and documented by a conservator, the repair looked as if it could have been made during the useful lifetime of the mask (Peever 1986). In this case the conservator had mimicked an existing ethnographic mend that used strips of baleen and sinew lashed together. Because of its appearance and the lack of documentation, the more recent repair could be misinterpreted as an original ethnographic repair. A treatment that avoided this confusion and still used baleen as a repair or replacement material is outlined below.

Conservators at the American Museum of Natural History recently treated a Tsatsalkwatal mask from the Northwest Coast that originally had a fringe of baleen fibers inserted into a series of holes around its perimeter. Remnants in the holes were identified as baleen, and an artist's rendering from 1909 showed the mask with strips of split baleen emanating from its outer edge like hair or fringe. In order to minimize intervention with the original object and make sure that the new baleen strips were not presumed to be the originals, a special mount was designed. Baleen strips were soaked in ammonia to break down the disulfide bonds, a process that enabled large sheets to be peeled into thin strips. The strips were then placed into a Pliacre epoxyputty mount, specially designed to accommodate the baleen strips while not having to be directly attached to the original object. With this technique, the conservators were able to avoid confusion as to the context of the repair. The baleen used for the repair was obtained through the mammology department of the American Museum of Natural History, New York. Under the Marine Mammal Act, all trade of marine mammal products is strictly forbidden. There are a few exceptions for Native Americans who hunt whales for subsistence purposes. In those instances, articles made from baleen must be significantly modified before they are sold.

Baleen has also been used by conservators as a support to strengthen weaker materials. An example is provided by Katherine Munro of the Canadian Museum of Civilization, who used some baleen strips to support broken feather shafts on a North American Indian headdress. Of a total of 22 splints applied to weakened or broken golden eagle feather shafts, 15 were made of split feather shafts and 7 were made of baleen. Baleen splints were used when the split feather shafts were too weak to support the weight of the broken feathers. The splints were adhered with a 30% solution of Acryloid B-72 in ethanol (Munro 1988).