Testing of waste vegetable oils as color modifiers in American walnut (Juglans nigra L.) wood

American walnut (Juglans nigra L.) wood is utilized for veneer due to its beautifully grained and dark-colored wood. This study was conducted to test the use of plant waste oils as color modifiers on American walnut wood. As waste vegetable oils, discarded walnut, olive, corn, and sunflower oils were employed. Following the application of waste oils to the wooden surfaces, various surface properties (brightness, color, and whiteness index: WI*) were determined. When the research findings were examined, it was observed that multivariate analysis of variance tests conducted for WI* values and color parameters were found to be statistically significant. For all vegetable waste oils, decreases were identified in L*, C*, ho, and b* parameters, as well as in WI* values and glossiness values (for all degrees and orientations). The ∆E* values were measured at 19.18 for sunflower, 22.02 for walnut, 22.65 for corn, and 19.49 for olive. Each of the discarded vegetable oils had an impact on altering the color of the wooden surface.