Conservation: The Theory
The course of a work of art through time is divided in three stages: birth, life and death.
The object is created by the artist, is exposed or stored and throughout its "use" is subjected
to various, simple or complex mechanisms of deterioration, until its complete destruction,
when it loses its aesthetic and physicochemical properties to the maximum. The role of conservation
is to prolong the life span of the work of art, delay or prevent the deterioration and eliminate the
possibility of death, thus ensuring the continuity of the cultural1 heritage of mankind.
The conservator is a well educated scientist, in fields like history of art, chemistry, physics and also in painting, museology and aesthetics. The conservation of a work of art involves three major methodological stages: investigation, conservation and restoration.
An essential requirement for the planning of the conservation program of a work of art, is that the conservator achieves the full comprehension of the object.
The work of the conservator begins with the aesthetic analysis of the object. The reference data (technique, dimensions, origin, inscriptions etc.) are being recorded and the object is stylistically interpreted (iconographic and iconological analysis). Beyond the description of the presented subject, the conservator must place the subject in space and time, so he or she can bear in mind the special characteristics of the age and place of origin of the object.
The second important step towards the integrated comprehension of the work of art is the physicochemical research. This involves the thorough description of the condition of preservation, as well as the specification of the morphology and the exposure of the object's technological particularities. Here the conservator clarifies the problems, in order to compose the methodology to solve them. The exact sciences contribute to the study of works of art, by offering valuable tools for the exploration of their technology and materials. These scientific methods are classified by their role in the investigation of the art objects, in three categories: as methods of examination, analysis and dating.
The examination methods are dealing with the surface or the internal structure of the objects. These are used for the documentation of the condition of preservation, providing us information about the construction techniques, decay of materials, as well as posterior interventions2. We talk about photographic techniques, concerning the ultraviolet, visible and infrared section of the spectrum, but also X-ray radiography and infrared reflectography (IRR).
The methods of analysis lead to the knowledge of nature and chemical composition of the materials. Typical examples of such methods are Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD).
Finally, the methods of dating offer the ability of direct dating of the construction materials, against relative dating which is the technique usually used in archaeology. These methods are based upon the study of the kinetics of several physicochemical phenomena, whose beginning is adjacent to the time of construction of the object that is being dated. Such methods are radiocarbon 14 and thermoluminescence (TL).
After the conservator has gained full comprehension of work of art, he moves on to the planning of the methodology of its conservation. This consists of interventions with retaining role, and their objective is the stabilization of the object. The friability of the construction parts is dealed with, e.g. by consolidating the strata of easel paintings (base, substratum, several paint strata, varnish). The range of interventions vary depending on the kind of object being treated - oil paintings, gravures, woodcuts, wall paintings etc. These interventions shield the object against future deterioration, as well as they retard or cease the mechanisms which provoke it.
The procedure of the restoration, that follows, improves the readability of the object. It involves interventions like cleaning and retouching. For instance, the treatment of a painting includes cleaning, where the conservator strips the layers of soot, dust and discoloured, oxidized varnish, which distort the hue of colors, while takes in account the value of patina, created by the passage of time on the object's surface. The documentation of the object's properties and the versatile aesthetic and scientific education enables the conservator to determine the correct degree of cleaning for the object. With the same outfit, he or she can deal with the complex ethic issue of retouching. Is it or is it not necessary? How, on which scale and to which degree?
After the conclusion of the energetic conservation, measures are taken for the preventive (or passive) conservation of the object. Energetic conservation does not solidify the object. It remains a living organism, an active part of civilization, therefore it must be protected even after its conservation. Preventive conservation mainly involves the regulation and control of the environmental parameters - temperature and relative humidity, radiation, airborne particles, noise - in order for the environment of the object not to contribute to its deterioration.
In our days, the value of preventive conservation is clearly stated by the global community of art conservators. Especially in the case of extremely large collections or lack of financial resources, preventive conservation is the only care taken, as long as, for some reason, there is limited or no potentiality at all for energetic conservation and restoration exerted on the works of art or the historic objects.
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