Ulay, G.Akter, M.Çakıcıer, N.Peker, H.Ayata, Ü.Atılgan, A.Çiftçi, S.2025-09-032025-09-0320251930-212610.15376/biores.20.3.7555-75732-s2.0-105012444482https://doi.org/10.15376/biores.20.3.7555-7573https://hdl.handle.net/20.500.14720/28392The effects of artificial weathering (168, 336, and 504 h) on the glossiness values and color parameters of varnished, polyurethane-modified ash wood were investigated. Samples included control samples without treatment and thermally treated samples under two different conditions (190 °C for 1.5 h and 212 °C for 2 h), all coated with a polyurethane-modified water-based varnish. In non-thermally treated and varnished samples, decreases in L* values were observed after weathering, while increases were noted in ho, C*, b*, and glossiness at 60° in both perpendicular and parallel directions to the fibers. After weathering, for samples thermally treated at 190 °C for 1.5 h and varnished, increases were observed in glossiness values at 20° and 60° in both directions, as well as in L*, b*, and ho values. Conversely, decreases were noted in a* and C* values. In samples thermally treated at 212 °C for 2 h and varnished, increases in a*, L*, ho, b*, and C* values were detected after weathering, whereas decreases were observed in glossiness at all angles (20° and 60°) in both directions. The ∆E* values showed a decreasing trend in non-thermally treated varnished samples after weathering, while an increase was observed in samples thermally treated at 212 °C for 2 h and varnished. © 2025, North Carolina State University. All rights reserved.eninfo:eu-repo/semantics/closedAccessArtificial WeatheringAsh WoodColorGlossinessWater Based VarnishArticle203Q2Q375557573