Correlation between softwood discoloration induced by accelerated lightfastness testing and by indoor exposure

The correlation between accelerated lightfastness testing and indoor exposu re in softwood discoloration was evaluated. The discoloration of softwood e xposed to indoor environments was simulated by using an accelerated lightfa stness tester equipped with UVA-351 lamps. The trends of the discoloration of three species of softwood (western hemlock, China fir, Japanese cedar) i n the accelerated lightfastness testing were similar to those in the indoor exposure test. Bathochromic effects occurred in the spectral reflectance c urves of wood with increase in exposure time, and consequently, its color t urned yellowish-red. Using the acceleration shift Factor (ASF), we could ob tain a correlation between accelerated lightfastness testing and indoor exp osure. Results from the ASFs of three softwoods examined indicate that disc oloration in the accelerated lightfastness test is 250 times more severe th an that in the indoor exposure test. (C) 2001 Elsevier Science Ltd. All rig hts reserved.