Color Parameters Comparison in Varnished Heartwood and Sapwood of Eucalyptus and Red Pine

This study compared the color parameters [∆a*, ∆C*, ∆H*, ∆b*, ∆L*, and ∆E*, a* (red color tone), L* (lightness), b* (yellow color tone), ho (hue tone), and C* (chroma)] of synthetic-based furniture varnish coatings applied to the heartwood and sapwood of eucalyptus (Eucalyptus camaldulensis) and red pine (Pinus brutia Ten.). The results showed that the variance analyses were statistically significant. In all wood species and wood parts, the varnish application resulted in decreases in ho and L* parameters, while increases were observed in a* and C* parameters. In b* parameter, an increase was observed after varnish application on red pine heartwood and sapwood, as well as eucalyptus sapwood, while a decrease was found in eucalyptus heartwood. The total color differences (∆E*) were measured as 9.49 for the heartwood of red pine, 9.20 for its sapwood, 7.41 for the heartwood of eucalyptus, and 12.55 for its sapwood. In red pine, the ∆E* values for heartwood and sapwood were found to be very similar, while a different result was observed for eucalyptus wood. The SPSS results from the study demonstrated the significance of the changes observed after the varnish application.