Colour change of finished and non-finished hardwood in outdoor conditions

Colour changes in wood in outdoor conditions, such as for building façades, outdoor furniture and urban artefacts affect and limit the use of wood. Within the framework of a large project on wooden buildings1, 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-thermal modifications of wood. 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; the colour changes are recorded as pictures (digital colour calibrated), as CIE-Lab coordinates., as gloss values and finally as Near Infra-Red spectra; also contact angle and reflectance to visible and to structured light has been measured on a sub-sample. In this paper CIE Lab coordinates are discussed. 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 from February 5th to April 16th .