General recommendations

It is strongly recommended that APSARA National Authority (ANA) projects be submitted to the groups of ad hoc experts through the ICC-Angkor Secretariat, for comments prior to implementation.

During restoration works conducted on the monuments, special attention will need to be paid to the treatment of the surface of materials that are the interface between the built work and its environment.
The surface layer therefore appears to play a crucial role both in terms of conservation and in terms of presentation of the monument.
This technical and aesthetic challenge as to what constitutes the “patina” of the building, leads us to make the following recommendations:
a. Given the possible protective role of the existing patina on old stones (fouling, lichens, algae, etc.), ill-considered systematic cleaning must be avoided.
Relevant testing and impact analysis of the proposed treatment on the physical structure as well as the aesthetics of the cultural property must be conducted prior to any such interventions.
b. In the same way, the issue of patina -essentially desirable when using recent materials to complete the works- must be appraised in all its aspects: method used to cut the facings, possible use of ancient tools (which remain to be better identified), artificial wear, and harmonization of colorings while a natural patina develops.

The technical solutions selected will need to optimize and reconcile as best as possible the various key criteria for conservation, sustainability and aesthetic integration.

To this end, when considering the final treatment of materials used in restoration works, the Committee recommends that all teams working on the site of Angkor ensure new elements blend in with more ancient elements that have been preserved, to ensure visual harmony.

Given the number of recent projects that aim to return long-disappeared selected statuary elements to various monuments, the ad hoc group of experts recommends a specific workshop dedicated to this topic be scheduled during a future session of the ICC.

The workshop should promote an in-depth approach to this issue, which is made complex in particular by the diversity of the technical solutions available:
– Return originals that were deposited in the past, or
– Replace them with copies made from casts or carvings.
The workshop should aim at defining a framework for a coordinated approach and a global policy in this area, which are essential to the understanding and the quality of presentation of Angkorian monuments.