The Performance of Different Whiteness Formulas for White Papers

Whiteness is an important property to characterize the surface color. A lot of whiteness formulas are used to characterize the whiteness of the materials. However, the performance of these formulas for paper samples is unknown. In this paper, 38 paper samples [27 fluorescent whitening agents (FWA) samples and 11 non-FWA] were evaluated under 6 light sources, including 3 levels of CCT (3000, 5000 and 6500 K) and 2 levels of ultraviolet (UV) radiation (with UV and without UV), by 12 observers (6 males and 6 females) with normal color vision. And 7 whiteness formulas were used to evaluate the accuracy of whiteness formulas in predicting the whiteness of paper samples using STRESS factor. The results suggest that WCIE and WUchida can predict the whiteness of paper samples more accurately.