Mid-Term colour change of finished and non-finished temperate hardwood due to natural and artificial ageing

We report the changes of temperate hardwoods in outdoor conditions. In a large project on wooden buildings , IVALSA is studying the evolution of colour changes on different wood species either without any surface treatment, either with various finishing and/or protecting products or processes, included hygro-thermic modifications of wood. The protective finishing cycles are either water either organic solvent based; the resins are the followings: alkyd, alkyd/acrylic, oil and natural resins. Also the properties of the layers are different, from transparent to thick brown. The main goal is to provide the behaviour of the different wood species, according to the protecting methodology adopted, due to the ageing effect deriving from the outdoor environmental conditions and from the artificial ageing; the changes are recorded as pictures (digital colour calibrated), as CIE-Lab coordinates, as gloss values. The contribution of visible and UV-A spectra, such as RH and temperatures are logged in field experimental set up. The tests here reported have been carried out along two years of natural ageing outdoor and twelve weeks of EN 927/6 QUV Panel artificial ageing.