ABSTRACT
ABSTRACT: Laser cleaning of stonemonuments is nowadays a procedure widely used in restoration. However, one of the criticisms to the method is the controversial yellowing of the stone. In this paper, we present evidence that aliphatic and aromatic carboxylic acids and phenols, which are components of a yellow fraction isolated fromblack crusts, are not affected byNd:YAG1064 nm laser irradiation.We deduce that thesewater soluble compounds, which always impregnate the stone surface underneath black crusts, cannot be removed by the laser beam when the crust is eliminated. Thismeans that, at least, part of the yellowish aspect after laser cleaning, is linked to these remaining compounds.
