II.1. Planning and Documenting Your Technical Exam

Before initiating a technological study of a bronze sculpture, we recommend establishing a multidisciplinary examination team. Such a group would ideally include at a minimum a specialist from the humanities (for instance a curator, art historian, or archaeologist), a materials or conservation scientist, and a conservator whose expertise encompasses some of both in addition to a good knowledge of artistic processes. Together they can clarify the questions surrounding the sculpture that the study should aim to answer and also identify which examination and analytical methods are likely to provide informative results. Additional questions may arise in the course of the examination.

Also essential is to identify the background research needs and literature to be reviewed in advance or in parallel to the technological investigation, and clarify desired outcomes and outputs, particularly with respect to the reporting of results (for instance in monographic studies or journal publications, or for integration in shared databases). Budget considerations and a desired schedule for completion are likewise important up-front elements of planning.

Given the broad range of questions to address and clues to look for on a bronze sculpture, it can be extremely useful to begin with an examination checklist that enumerates subjects to be investigated. A checklist, or report template, can facilitate the systematic recording of observations that may ultimately help answer questions about the sculpture under study. Therefore, when designing an examination checklist or report template, it is critical to consider the specific questions and desired research outcomes that underlie the study. Several useful examples of examination checklists/reports developed in the past by bronze sculpture researchers are presented in “Appendix: Document Library”. It is noteworthy that there is considerable variation in the length and specificity of the documents presented here; the particular circumstances of any given research program will determine which type of checklist may be most useful. Note that electronic notebooks are increasingly used by conservation scientists and archaeologists in the field.

As those who engage in such research can attest, it is crucial that the various team members involved in the project be kept abreast of—if not actually personally involved in—the various steps of the technical examination and analysis to ensure that as new discoveries and observations are made, each participant may contribute their interpretations and identify potential new lines of inquiry.

The amount of time required to conduct a technical examination of bronze sculpture can vary dramatically. The simple examination of a small statuette without the application of any scientific analysis might be completed in less than a week, including reporting, while an in-depth technical study of a series of large bronzes from different international collections might take years to organize and execute. Some indication of the time required to pursue technical studies may be gleaned from several of the case studies presented in this work (see the “Synopsis of Technical Parameters” sections at the end of Case Studies 2, 3, 4, and 5).

Normally, the physical study of a bronze sculpture begins with a close visual examination. Lighting conditions in galleries, in storage rooms, and even in dedicated laboratories are often insufficient to observe surface details properly (an activity that is often key for understanding the work) or subtle variations in patina. Both the intensity and the spectral distribution of examination lighting are important.

Some tools and equipment are nearly indispensable in the initial visual examination of a bronze sculpture. Following are recommendations from experienced examiners:

• Overall lighting. A bright and evenly lit room is a tremendous asset (see above).

• Notebook and/or audio recording device.

• Gloves. Gloves protect the sculpture from fingerprints and soiling. Nitrile gloves are widely preferred, though latex and cotton are commonly used.²

• Flashlights or other directional light sources. Intense, focused light is important for seeing into and through dark patinas as well as for creating localized raking light.

• Measuring tools. A cloth measuring tape, as used by tailors, is useful for measurements directly on objects, and a traditional, stiff measuring tape is also essential. A variety of calipers can be helpful, including Vernier, dial, or digital calipers for fine measurements, as well as different sizes of outside and inside calipers for measuring wall thicknesses, void dimensions, and so on (fig. 366). For overall measurements, a drafting or framing square, combined with square sheets of cardboard or foam core, and a bubble level are useful to make accurate measurements. See II.4.

• Camera with macro capability and tripod. See II.2§1.

• Color reference card, a scale bar, and a pointer are necessary for good photo documentation (see II.2§1.1).

• Magnifying eyewear. A wide range of specialized head-mounted magnification systems are available. Reading glasses with magnification of +7 are a low-cost alternative.

• Tools for macro and microscopic examination. Higher magnification than is available as eyewear is often desirable. Tools can range from an affordable hand lens (loupe) to very expensive articulated stereomicroscopes or high-end digital microscopes. Relatively low-cost USB microscopes or cell phone adapters may be an attractive option. The ability to record images of good quality is advantageous for documentation.

• Ultraviolet light (and protective eyewear). For initial examination, a handheld ultraviolet lamp is usually satisfactory (see II.2§3.1, I.4§1.3, I.8§3.1, fig. 191) Relatively low-cost LED flashlights are now available, with even distribution and high intensity; the most useful emit at 365 nm. The ability to darken the examination room is important.

• Mirrors. A selection of small inspection mirrors of different sizes can be useful for looking under or inside sculptures. Inspection mirrors often have an adjustable swivel mount at the end of a telescoping handle.

• Magnets. A strong magnet is useful for detecting core pins and other ferrous components (see I.1§3). Many practitioners place a small rare-earth magnet into a folded piece of tape. This provides a “handle” for the magnet and prevents direct contact with the object’s surface. Even slight attraction of the magnet can be detected by observing flexing of the tape handle.³

• Simplified line drawings or photographs from different angles are useful for graphic documentation of features such as joints, repairs, or damage. Printed images can be marked up with colored pencils or marker, and digital files can be annotated digitally.

• Tools and containers for sample collection. These will vary depending on the type of sample to be collected. See II.5§3.5, II.6§3.1, II.7§3, II.8§1.4, II.8§2.4.

Open viewer Figure 366

Open viewer Figure 191