The performance of several UV inhibitors (light stabilizers and hindered amine light stabilizers) was investigated in a polyester gelcoat. The color change and the gloss retention were evaluated using several known accelerated lab test instruments and procedures, against real-life outdoor weathering. Correlation between these methods and the real-life data was suggested, along with a proposed model of the whole weathering process: upon outdoor exposure the color change (yellowing) occurs first, then after at least one year of weathering, the process of gloss loss also starts. (C) 2003 Wiley Periodicals, Inc.