Colour stability of steamed poplar wood during short-term photodegradation

Abstract

Plantation poplar (Populus x euramericana cv. Pannonia) wood samples were steamed at 100 °C, 110 °C, and 120 °C and then irradiated by a strong UV emitter mercury lamp to test their colour stability. The colour change was evaluated and presented in a CIE Lab colour coordinate system. For the control, unsteamed poplar specimens were irradiated using the same mercury lamp. A considerable increase in colour saturation in the specimens was generated by steaming, and the saturation value further increased during the UV treatment. The lightness value of the unsteamed control specimens decreased continuously during the entire UV irradiation period. In contrast, the lightness value of the steamed samples decreased only during the first seven hours of the UV treatment and remained constant afterward. Steaming enhanced the redness stability of the poplar wood against UV irradiation. Modification of wood components during steaming at 120 °C stabilised the poplar wood redness against short-term photodegradation. Steaming slightly reduced the yellow colour sensitivity of the poplar to photodegradation.