Each object is individually assessed to determine its current condition and vulnerability, the specific exhibit hazards to which it will be vulnerable during display, and to provide an overview of treatment needs.
What is the purpose of the object condition and vulnerability assessment?
Although objects should be first proposed for exhibit with conservation concerns in mind, each object should now be assessed by a conservator to conclusively determine its suitability for exhibit. The conservator will evaluate the object’s current condition and also its specific vulnerabilities to exhibit hazards, such as humidity, light exposure, and temperature fluctuations. The results will be used by the conservator to help establish the object’s conservation requirements: the level and type of protection the object will require while on exhibit.
Specifically, the condition and vulnerability assessment will help to:
- • Determine whether an object is too vulnerable for display in the proposed exhibit. Certain objects may be too fragile or too deteriorated to be displayed under any but the most stringent safeguards. Other objects may not be in a condition that is sufficiently stable given the specific requirements of the exhibit plan. For example, a deteriorated 19th century wedding dress that could be safely displayed lying in an enclosed exhibit case, would not be suitable for an exhibit plan that calls for open display on a mannequin in an historic structure.
- • Identify objects that are in unstable condition but could be stabilized through conservation treatment and thus made ready for display. For instance, iron scissors that are covered with rust could be stabilized to allow display.
- • Indicate what treatment objects will need before going on display. The assessment will provide an initial estimate of the conservation treatment objects will need before going on exhibit. General time estimates for treatment can also be provided; for instance: “Iron scissors: corrosion removal and protective coating; 2 to 4 hours.”
- • Identify an object’s level of vulnerability to the hazards posed by exhibition, such as exposure to pests, dust and inappropriate levels of humidity and light.
- • Refine budget estimates by indicating what the collection’s vulnerabilities are, what conservation measures will be required to safely exhibit an object, and what level of object treatment must be anticipated.
- Note: There are no universally accepted condition descriptions or vulnerability descriptions. One practical approach is to describe the objects as “extreme,” “high,” “moderate,” or “low vulnerability.” “Vulnerability” here indicates an object’s susceptibility to damage from the nine sources of deterioration. Those termed “low vulnerability” are those deemed least susceptible to damage.
Illustration: Guide to Exhibit Object Vulnerability: Table for Identifying Broad Classes of Vulnerability
Why should each object be assessed individually?
Objects are endlessly diverse. They can differ as to the materials from which they’re composed, the process by which they were created, and their unique history of exposure to damaging conditions.
It is therefore essential, even with collections of seemingly similar objects, to evaluate each object individually and identify its specific treatment needs and vulnerabilities. For example, two similar printed documents produced only a few years apart could nonetheless have different levels of vulnerability to light. The more recent type of ink could be very fugitive and unable to tolerate much exposure to light, thus making the more recent document a less desirable choice for exhibition.
Following are three key factors that conservators use to calculate an object’s vulnerability to damage:
- 1. The materials from which an object is made: Museum collections comprise the full spectrum of materials, from relatively stable stone to metal and fabric, leather, and paper. Decades of research have identified the various environmental factors likely to damage these different materials and accelerate their decay. Museum objects will therefore vary in their response to environmental conditions and rate of deterioration depending upon their composition. While excessive lighting will do little harm to a stone sculpture, for example, it could quickly fade the decoration on a similar stone sculpture with painted elements.
- • Generally speaking, objects made from organic materials are more vulnerable to the hazards presented by exhibit conditions. Accordingly, organic materials tend to possess more stringent conservation requirements than inorganic materials. Conservation treatment can also be more time-consuming.
- • Mixed media or composite objects can have many more vulnerabilities than a single component object. There is the added complication of possible interactions between the different materials, such as glues and adhesives, and the possibility of physical weakness at joints and laminations.
- 2. The manufacturing process used to produce an object: Certain manufacturing processes introduce greater vulnerability. For example, leather that was chrome-tanned is much less vulnerable to high humidity than is leather that was vegetable-tanned, in which high humidity can accelerate deterioration and rotting.
- 3. The current condition or state of deterioration of an object: The object’s current condition is the best indicator of its stability, the treatment it requires and how it will hold up under the rigors of exhibition. The stability and durability of an object can be determined by reviewing the condition of both its structure and also its individual components (e.g. the extent of physical-, chemical- and biological-induced changes such as weakening, stiffening, percentage of loss and overall damage).
Illustration: TABLE: TEN AGENTS OF DETERIORATION