NC and CA thin films (4e30 mm thick) were submitted to arti-
ficial accelerated photodegradation under UVevisible light irradiation
(l > 300 nm, 60 C) in ambient air. Irradiations (l > 300 nm)
of the thin films were performed in a SEPAP 12/24 unit, which was
designed for studying polymer photodegradation in artificial
ageing with medium-accelerated conditions. These accelerated
degradation conditions are representative for outdoor weathering
and as they are even more drastic degradation conditions than
those in museums (l > 340 nm), they were chosen to study both