The Shades of Color of Quercus robur L. Wood Obtained through the Processes of Thermal Treatment with Saturated Water Vapor

Abstract

This paper presents the shades of color of Quercus robur L. wood obtained in the processes of thermal treatment and color modification by saturated water vapor, with temperatures: t(I) = 112.5 +/- 2.5 degrees C for tau = 5.5 h (mode I), t(II) = 127.5 +/- 2.5 degrees C for tau = 6.5 h (mode II), and t(III) = 137.5 +/- 2.5 degrees C for tau = 7.5 h (mode III). The color of oak wood by thermal treatment in mode I changes minimally with mild browning in the CIE-L*a*b* color space: L* = 65.5 +/- 1.7; a* = 8.8 +/- 0.4; b* = 20.7 +/- 0.5. A brown shade with coordinates: L* = 56.8 +/- 1.3; a* = 9.3 +/- 0.5; b* = 19.4 +/- 0.5 is achieved in mode II. Oak wood thermally modified by mode III acquires an original brown-gray color with the color coordinates: L* = 47.5 +/- 2.1; a* = 9.4 +/- 0.5; b* = 17.1 +/- 1.1. The irreversible changes in the color of the oak wood, achieved by some of the color modifications of wood using saturated water steam, extend the possibilities of its use in the field of building-joinery, the artistic field, and the field of design.