engleski

Sapwood and heartwood colour variability of steamed cherrywood (Prunus avium L.)

During the steaming treatment of wood, there is intention to achieve more intensive and homogenous colour of wood or to vary its hue. Influence of steaming on colouring of sapwood and heartwood tissue was researched on cherrywood (Prunus avium L.). Randomly selected cherrywood boards, in green state, 43 mm thick, were indirect steamed for period of 18 hours, at temperature of 70°C. Wood samples were extracted every 3 hours and colour was assessed with standard 3-stimulus colorimeter, using CIEL*a*b* system. The colour was compared to starting untreated colour of cherrywood. There was significant heterogeneity of hues found out on specimens during hydrothermal treatment, both sapwood and heartwood. Steamed cherrywood sapwood and heartwood significantly differentiated during the process, especially in lightness (L*) of wood colour. Finally the colour of steamed cherrywood was more or less uniform considering all of important colour characteristics. During the steaming process the sapwood has declining trend of lightness, and in the same time heartwood has increasing trend of lightness. The calculated covariance proved that during steaming process the lightness, chromaticity on blue – yellow axis and saturation of sapwood and heartwood are related to steaming time at constant temperature. Further goal will be the determination of chemical compounds that produce such effect in steaming process and further variation of steaming time and temperature. There is clear indication of importance and usefulness of colorimetry to asses and control steaming process of wood.

cherrywood (Prunus avium L.); sapwood; heartwood; wood colour; steaming process; colorimetry; CIEL*a*b* system

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