the treatment of a surface to make it impermeable. An operation of great importance in the construction of buildings that need to be protected from the infiltration of water and humidity from the soil beneath and from the atmospheric elements above.

ultraviolet rays, invisible to the human eye, when they hit an object can be absorbed or reflected in different ways according to the substances and materials contained in the object. Ultraviolet rays provoke the phenomenon of fluorescence in the older elements of an object. A disadvantage is that the more modern the materials, the less fluorescence they produce. This phenomenon can be photographed or perceived using an instrument that emits ultraviolet radiation allowing the viewer to observe the added functions of the different fluorescence of the materials on the surface, thus highlighting all the alterations. This allows the distinction between old strata and those more recent and also the identification of micro organisms.

is based on the differing density of the materials of the object. The short length of the waves enables them to penetrate extremely effectively into the material. This method enables the effects to be photographed, indicating the effects of minor and major absorption of the electromagnetic waves in the material. This procedure also reveals the areas in which alterations have taken place, identified by the differences in density based on the differing materials present. Often radiography is indicated as the most appropriate scientific method for the structural study of a work of art. The radiographic examinations must be combined with other methods of analysis in order to obtain a more detailed study of the object. The use of x-ray does not only identify the state of conservation of the material but also the presence of alterations and repairs.

this technique allows the qualitative and crystallographic analysis of any crystalline substance; therfore useful in the identification of pigments, contaminating salts, corrosive products, metallic elements, stone and ceramics.

an analytical methodology that uses an x-ray source and a receptor that determines the minerals present in a sample.

this is used to analyse the surfaces of the organic material of a different or varied nature e.g. metals, pigments, ceramics, glass, stone, corrosive products.

hydro repellent material used in restoration capable of penetrating absorbent construction materials that vary in order to aid water resistance. It is applied until saturation using a brush, spray or vacuum.

a technique used to repair lesions in the wall structure that consists of demolishing the part corresponding to the lesion in order to reconstruct the damaged part, thus anchoring the replacement part to the original, re inserting new bricks into the spaces created in the demolition.