Resumen de Aiming for prevention and maintenance, not restoration
Rather than mitigating damage, the aim of archaeological conservation should be to prevent it. To prevent it, the causes of deterioration must be known. The most common cause of deterioration of wall paintings is the phenomenon of saline eorescence, which typically originates from the presence of groundwater and soil moisture, rich in salts, and can be aggravated by external inltrations or the presence of animal wastes. Efforescences also arise from the original building materials, and much more than should be the case, from the materials used in restoration. The use of modern cements brings sodium and potassium alkalis and becomes the main cause of the saline efforescences. Water provides the vehicle for transporting the salts. The evaporation of the water brings about their crystallisation. Depending on their porosity, the walls are affected by an inexorable cycle of evaporation and condensation, dissolving and recrystallisation of the salts. The excavation of the wall represents its moment of greatest fragility. e current article establishes base terminology, consistent with the recommendations of the ICOM Conservation Committee, and explains the origins of the philosophies of ‘preventive conservation’ and ‘programmed conservation’. When these philosophies are ignored, the excavation campaign will lack a preventive strategy, and the end result will be the proliferation of damage. The correct approach to preventive archaeological conservation should always include the study of the excavation environment, the understanding of the dynamics of local degradation and the development of prevention and intervention strategies.
