Conservators can have a variety of roles on an archaeological site. In some cases, I act as a registrar and a conservator, in others these are two separate roles and I am only employing conservation methods to stabilize the collection. However, there are some archaeological projects that don't include conservators at all. At what point should a project include a conservator? When does a process become a "conservation treatment" versus just brushing an object off? Where is the line between removing dirt during excavation and "cleaning"? When does conservation begin?
This last question is one that is not sufficiently answered in the profession, nor should it be. It should be a constant discussion and change through the generations. Conservation professionals from different backgrounds and who work within different specialties may each give a different answer. Here's my two cents:
Conservation is an active process that begins the moment that interventive processes are used in an effort to reveal information about an object or to stabilize it in its physical form.
So, is cleaning a conservation treatment? Cleaning can happen when the archaeologist removes the object from its in situ location and brushes the loose environmental sediments from the surface or if a curator dusts a painting on a museum wall. The conservation phase would begin if the object requires an advanced mechanical cleaning beyond removing the loose environmental products (dust, dirt, mud). Cleaning an object of patina, tarnish, rust, concretion, or any other product related to that objects material composition or the deterioration of that material requires an awareness beyond gentle brushing or cleaning. You begin to ask questions like: Is it stable enough to be brushed further? Where is the original surface as opposed to the corroded surface?
Conservation begins if you are removing deposits that originate from the object (and aren't just environmental).
The reason why this type of cleaning is considered a conservation practice is because it is part of the stabilization as many of the deterioration products can cause further damage if left in situ.
Another example raised in a thesis by Sophie Carman from East Carolina University relates to the interference of conservation treatments on organic residue analysis. Archaeologists often subject pottery and other excavated materials to a brushing and/or soaking process to reveal more information about the object. These materials are then reassembled by the archaeologist or students. In some cases this is done because it has always been what the archaeologist has done to analyze the artifacts and a conservator isn't seen as necessary. In other cases, there is such a large amount of material excavated from the site that it is too much for one conservator to work with in the time allotted, so the conservator may only advise on techniques and products. So the question is then posed again, when does conservation begin in this situation? I would suggest that the process of doing more than simply brushing the material could be classified as a conservation process. Exposing the excavated material to water in a soaking process is an interventive process (i.e. one where you are subjecting the object to an invasive procedure).
Is brushing an object an archaeological process or a conservation process? Both! Brushing an object can reveal information that can help with interpretation, but once it goes beyond removing loose sediment, you need specialized training to understand the material and prevent any damage from the cleaning process. Overcleaning can be an irreversible process that removes the original surface of the object (including any inscriptions or raised surfaces).
Is soaking an object in water an archaeological process or a conservation process? Conservation. Archaeology is the discipline focused on the recovery and interpretation of material culture and those factors that were impacted by and that made an impact on humans. Archaeological conservation is the discipline that reveals the information contained in the object through specialized knowledge in an understanding of the environment and material type in an effort to stabilize the material for interpretation. Is it the conservators responsibility to interpret the object past the physical features? Is archaeological conservation just a technical skill within archaeology? Those are great questions! But, back to this one: Conservation begins when you are using invasive cleaning techniques or exposing the object to chemical treatments (yes, water is a chemical). Exposing an object to water can cause irreversible damage if you don't have experience in working with that type of material. Most archaeologists specialize in a specific geographical area and have decades of experience working with material culture from that site or area and therefore have a good understanding of what cleaning processes are successful and which ones aren't. That doesn't mean that those processes aren't entering the realm of conservation.
At what point do you believe conservation begins? Whether you are caring for a sculpture, a painting, or a historical object, when do you need specialized skills? Leave me a comment!