Colour Change of Steamed Alder Wood Caused by UV Radiation

Alder wood (Alnus glutinosa L.) was steamed with a saturated steam-air mixture at temperature of t = 95 °C, or steam 115 °C and 135 to obtain pale brown colour, light red-brown colour dark brown-grey colour. Subsequently, samples unsteamed alder were irradiated UV lamp in Xenotest Q-SUN Xe-3-HS after drying order test the stability wood. The change surface evaluated by means measured values on coordinates space CIE L*a*b*. results show that as well darkened browned due photochemical reactions caused radiation. opposite tendency recorded where deep dark-brown-grey lightened brown-reddish shade under influence analysis changes L*a*b* shows greater darkening browning steaming, smaller ΔL*, Δa*, Δb* positive effect steaming resistance is evidenced decrease overall difference ΔE*. While value total radiation ΔE* 10.9, it decreased 8.7 for which 20.2 %; 6.5, 40.3 water 5.7, 47.7 %.