The wall painting surfaces represent the main challenge for the laser cleaning techniques. The
objective of this work has been the study of the laser cleaning technique when applied to wall
paintings. In particular, this study has been devoted to understanding how the characteristics of the
laser apparatus and its specific use are linked with the nature of the substances to be removed from
the painting. A number of artificially wall paintings were selected with paint layers that were
composed of different pigments and covered with different dirties. In this work the feasibility of laser
cleaning for the removal of dirties from the wall painting surfaces using Q-switch Nd:YAG laser
operating at two different wavelengths: in the infra-red and in the visible (1064 and 532 nm) is
presented. The effectiveness of the cleaning process was monitored by following the disappearance
from the LIBS spectra of the deterioration aspects elements during successive laser shots. The aim
of this work is focus on the definition of the experimental boundary conditions in which laser cleaning
can be safely applied in cleaning of the deteriorated wall paintings.