Week 10 of 12
Module 5: Conservation Interventions and Treatments; Criteria for Selection and Implementation
Andrew Thorn, a conservator from Australia, came to talk to us today on his specialism; rock art. One of the main focuses of these lectures was the philosophy and human understanding related to this type of conservation. Andrew's experience of this work includes a large number of cases where the rock art still belongs to a group of people or community; generally an indigenous population. This introduces many more considerations than simply rock art as a piece of a heritage long-gone and the significance of the work or surrounding environment must be treated in a very different way. Andrew believes that a strong and trusting relationship between himself and the custodian(s) of the art are necessary, along with a respect for the related culture and community, although he believes it to be necessary to take a 'professional disinterest' in the significance of the art. That is not to say that he is not interested in its origins or meanings, but that they are not required for him to do his job and in many cases they are either secret or private symbols, meanings or stories. If the information is available for him he will find this out in time, but not by asking.
This topic led to a discussion about how the interaction of a community group with an object can vastly affect the approach taken. Andrew showed us an example where a termite nest had grown rapidly and concealed an area of rock art and with the agreement of the community this was carefully removed by a conservation procedure and the art work revealed. Simon Warrack at this point gave an example where a 4m high turmite nest has grown in Angkor Wat (see Friday 10th June 2011; Water repellants, Consolidants & Conservation of Paint on Stone) but which has not been removed because it has taken on a level of significance. The nest is believed by many to have grown into the form of a Buddha and is now considered to be a sacred monument and in addition, because the site has a history of Buddhism, the turmites cannot be killed. An interesting point in relation to 'living' pieces of rock art is that the markings may not be the thing which has the most significance to the custodian(s) or community; it is often the rock itself which bears the meaning and therefore conservation interventions need to be considerate of this point. A consolidation treatment may save the superficial markings but they may be considered to damage the significance of the site.
Rock art tends to fall into two categories; 1. engravings into the rock surface (hammering often used) and 2. paintings or markings applied using a different material onto natural rock surfaces. Andrew argued that the significance of a site tends not just to be in the image alone, but that the whole context of the site and its surrounding area need to be considered. Salt damage is an even more complex problem in the case of rock art than it is in buildings, because you do not have the same options of desalination or damp proof courses. If you do try to remove a salt via a poultice you face an additional danger that more salts will be transported into this area by osmosis which may enhance the previous damage.
This afternoon we visited the tombs that we're working on in the Non-Catholic Cemetery to make decisions on (and in some cases apply) biocide treatments. Anita and I assessed the tomb of Florence Baldwin that we're working on and following a debate and discussion with others took the decision not to apply a treatment. This decision was based on the fact that we could not observe any damage related to the presence of biological growth and we do not believe that the biology present detracts from the appearance of the tomb. We still have to decide if we will remove some or all of the lichens mechanically at a later stage based on damage risk and aesthetics.
Several of the various forms of biological growth present on the tomb of Florence Baldwin can be seen in this image including the darkened upper surface, yellow lichen growth on upper surface and white lichen growth on the side of the tomb.