Fig. 9From: The influence of light and relative humidity on the formation of epsomite in cadmium yellow and French ultramarine modern oil paintsNormalised XPS spectra for W&N French ultramarine paint samples on acrylic-primed canvas aged at 50% RH and 75% RH with ambient light and elevated light conditions respectively, left to right, for environments: a C 1s; b O 1s; c Mg 1s; d Na 1s; and e S 2pBack to article page