The wall paintings, both if fresco or secco paintings, have a very specific set of problems, cause they gather into a single artefact characters of figurative works with those of a wall structure and therefore the risk factors related to them. Also the diagnostic investigations should also take account of this dual nature, and then study both the structure as the image.
The techniques used are essentially non-destructive: grazing light photograpy, NIR reflectography, UV fluorescence photography and colorimetry for the description of the painted surface and of the preparatory layers; the portable X-ray fluorescence of the pigments; the thermovision to evaluate possible plaster detachment; microbiological tests for identification of microorganisms.

If necessary, we can also proceed sampling material, as little as possible. On such samples can be performed stratigraphic cross and thin sections to be observed by microscope or by the il EIMA software, analyses by electron microscopy with microanalysis for the recognition of layers and pigments, FTIR spectrometry on organic substances,(previous treatment, retouching, “velature”) and ionic chromatography for very damaging soluble salts inside the masonries.