ÇATALHÖYÜK 1995 ARCHIVE REPORT

Research undertaken in 1995 for the conservation of mural paintings and architectural sculpure

Prof. Frank Matero and Constance S. Silver

INTRODUCTION: STATEMENT OF PURPOSE

The purpose of this report is to summarize the research undertaken by the investigators in 1995 to develop conservation treatments for the mural paintings and architectural sculpture of the pre-eminent archaeological site of Catalhoyuk, Turkey.

Field reports of the excavations carried out in the 1960S strongly indicate that outstanding multi-layered mural paintings and architectural sculpture will be discovered as the site is excavated over the next twenty years. The focus of the investigators' research, therefore, is to develop methods that will address several requirements for conservation: stabilization of murals and sculpture in the field, as excavations are carried out; safe removal of murals, relief sculpture, and architectural features to the laboratory; conservation of murals and relief sculpture in the lab; the separation and conservation of multiple layers of mural paintings; methods for remounting and display of murals and relief sculpture in the museum and possibly the field, and safe long-term storage or maintenance.

In 1995, this research was carried out in three principal phases: preparatory research in the United States; one month of field study at the site during the excavations that were undertaken in September; and continuing research at the University of Pennsylvania on specific issues of conservation.

PHASE 1 - PREPARATORY RESEARCH

The authors were provided with samples of plaster from the 1994 excavation. Initial examinations suggested highly unusual properties and a rather poor response to standard conservation treatments. For these reasons, a wide range of conservation materials were transported to Turkey, to address any conservation problems that could arise during the 1995 field season.

PHASE 2 - 1995 FIELD RESEARCH

Prof. Matero remained at the site from August 29 to September 4, with Ms. Silver. During that time, the authors were able to examine the condition of plasters that had been excavated in the 1960s, backfilled and then re-excavated in 1994 and 1995. Several general characteristics were noted: the plasters are remarkably white, dense and thick, composed of up to 80 superimposed strata. Because of their exposure to the elements, the plasters manifested varying types and degrees of deterioration, such as surface erosion, loss of adhesion from the wall, delamination between layers and general loss of cohesive strength.

These plasters were used for the first pilot conservation treatments in the field, with surprising results. During the authors' previous conservation work on early pre-Hispanic sites in the American Southwest, water has always been the most critical "material" of conservation because its application results in the re-hydration and re-plasticizing of the plasters. That is, rehydration allows re-establishment of the original plastic and dimensional qualities of the plaster and restoration of cohesive strength. By contrast, at Catalhoyuk, water actually provoked the rapid destabilization of the plasters by causing them to swell and disintegrate. Isopropanol and ethanol were found to be equally damaging.

Further studies in the laboratory at Catalhoyuk, followed by field testing on newly excavated murals, indicated that the addition of organic amendments, such as very small amounts of proteinaceous materials to the water, mitigates the effects of water alone and permits rehydration. During the 1995 excavation, intact multi-layered mural paintings were discovered in very poor condition: the murals were detaching from the walls and delaminating as friable strata. Injections of water amended with small amounts of rabbit skin glue and compaction of dampened surfaces through wet-strength tissue stabilized the murals sufficiently to allow excavation of the room to be completed.

Acrylic resins also provided good results for the treatment of some problems of reattachment of layers; on similar types of plasters from other sites, acrylic resins have often caused changes in optical qualities that results in a darkening of the plaster and paint. The plasters of Catalhoyuk exhibited strong resistance to shifts in optical qualities.

In addition to on-site examinations and testing at the site, the authors were able to formulate an innovative philosophical and technical response to the broad challenges presented by the murals and architectural sculpture of Catalhoyuk. It was concluded that significant walls must be conserved, moved and retained as architectural and artistic units, rather than simply excising and preserving a particularly splendid detail, such as a "goddess" sculpture. Heretofore, what might be described as the museological collection of artistic "trophy heads" has characterized the manner in which the architectural arts of sites have been treated throughout the world. This dismemberment is both destructive to the cultural property and ultimately misleading to the viewer, who will have no sense of the intended artistic or symbolic function of the excised element.

Briefly described, the authors hypothesized on site that ft will be possible to strengthen and stabilize entire wall surfaces by consolidating them with a category of inorganic consolidants referred to as ethyl silicates. Once consolidated, the wall and its features can be treated much like a veneer and cut away from the masonry support as a panel and then transported to the lab for comprehensive conservation and ultimately for museum display as an original integral unit.

The third phase, to be carried out at the Architectural Conservation Laboratory of the University of Pennsylvania, will be research that will test this hypothesis through laboratory research on plaster consolidation and detachment methods and the construction of scaled models of murals and sculpture for replicated disassembly. (Partial funding for field conservation expenses was made by the Samuel H. Kress Foundation).

PHASE 3 - EXPERIMENTAL RESEARCH AT THE UNIVERSITY OF PENNSYLVANIA

Research currently underway at the Architectural Conservation Laboratory of the University of Pennsylvania includes two Master of Science theses in Conservation focused on the problems of plaster consolidation and the detachment of superimposed mural paintings at Catalhoyuk. Full descriptions of these research projects accompany this report. In addition to these material studies, a third project is also in progress under the supervision of Prof. Lindsay Falck (University of Pennsylvania), focused on the development of methods for the protection, detachment, removal and transport of the architectural features (walls, relief sculpture, pilasters, benches, etc.) for later conservation treatment and possible re-installation.

The results of all three research projects will be tested in a half-scale replicate model of several walls or a room from Catalhoyuk. This work will provide much-needed data for potential treatment strategies on site next season (1996).

RECOMMENDATIONS

To date, the 1995 field testing and 1995-96 experimental research at the University of Pennsylvania represent the first three phases of a mufti-phase conservation program described in earlier proposals for the development of a comprehensive conservation plan for the mural paintings, reliefs, architectural features, and site in general. It is anticipated that the results of this work will be applied during the next phase of work during the 1996 field season. Depending on the progress of excavation, every effort should be made this season to fully implement the methods proposed in order to assess and modify the techniques for future application. To implement the temporary stabilization, consolidation, separation, and transport of the architectural features for subsequent laboratory analysis and treatment, it is recommended that the conservation team including Matero, Silver and Falck, accompanied by two or three conservation graduate students, participate in the 1996 field season. Depending on the progress and results of the excavation, Drs. Paolo and Laura Mora will also be required to advise on the final techniques for treatment. Schedule, funding and site logistics will all need to be determined in the coming months in order to plan for the next conservation field component.