Effects of density on colour and gloss variability changes of wood induced by heat treatment

Abstract

AbstractThe influence of heat treatment severity (resulting from temperature) on the colour and gloss distribution changes of mahogany wood, and the effects of wood density on the responses to heat treatment were evaluated. The wood timbers with different densities were treated at 150°C to 200°C with an interval of 10°C and duration of 4 hours for heat treatment schedules. The colour parameters (lightness L*, red‐green axis value a*, yellow‐blue axis value b*) and gloss (parallel and perpendicular to the grain) values of heat‐treated wood were determined. The distributions of colour and gloss were analyzed using a frequency counts method. Results show that heat treatment resulted in the distinct decrease in L* and b*, while almost no change in a* for mahogany wood. The lower gloss values were obtained in the wood after heat treatment. The colour and gloss uniform on the exposed surface of the wood was improved due to heat treatment. Heat‐treatment induced colour and gloss changes were more effective in the samples with lower density. The effects of density on the colour and gloss variability in the original wood were reduced by heat treatment, and this reduction was more distinct at high heat treatment temperature. The total gloss change was found to be highly correlated with the total colour change of heat‐treated wood.