CIE orthogonal and cylindrical color parameters and the color sequences of the temperate wood species

In spite of the value of color information in woodworking praxis, the color coordinates, color values and other optical properties of wood and lignocellulosic materials are less systematically known and used than their physical mechanical and chemical properties. This paper discuss the advantages and drawbacks of using color information on wood and presents the results on 25 temperate wood species. The data of the 3 orthogonal and 2 cylindrical color parameters of the 8 softwoods and 17 hardwoods have been localised in the standardised CIE system. The "wood-like color space" has been defined as follows: L*(min) = 44.41, L*(max) = 90.49; a*(min) = 0.62, a*(max) = 18.4; b*(min) = 16.10, b*(max) = 31.54 and the CIE coordinates of the centre of the wood color data cloud of the temperate wood species are L* = 72.8 +/- 9.5: a* = 7.5 +/- 3.5 and b* = 21.5 +/- 3.7. The probability density distribution curves calculated from the standard deviations have been used for the visualisation of the relative variability of the color parameters L*, a*, b*, C*, H degrees set of the comparable sets of the samples of the wood species with 90 parallel measurements for a specie. The temperate wood species have been ordered in the 5 CIE color sequences according to lightness (L*), redness (+a*), yellowness (+b*), chroma (C*) and hue (H degrees). The visualisation in the CIE space has indicated that the individual wood species differ in measure of unity/diversity, the angel orientation, correlation of color parameters and the shape of the color data clusters. It seems that it would be possible to use colorimetry for recognising of wood species and natural materials.