In 2015, Golden performed lightfastness testing on this blend. At that time, it had an estimated equivalent of ASTM I. In 2023 Golden performed rigorous tests in various mixing whites. As a mixture, this color does not appear to have been specifically mentioned, however it is worth noting that Golden published groundbreaking lightfastness testing in various white colors. The choice of mixing white may affect the performance of certain pigments. See https://justpaint.org/astm-lightfastness-testing-for-oil-paints/ for more information.