Please note that genuine chrome and lead colors are toxic. As with other artists colors please refer to information from the manufacturer about the composition as well as the risks of handling these materials. (We are artists, not toxicologists, so please always refer to the manufacturer and third party toxicology experts for health info regarding the paints in your practice). The Paint List also recommends seeking the opinions of multiple third party health and safety specialists for information about hazardous materials contained in artist paints. In regards to lightfastness, there is new research regarding one of the pigments in this blend. This color contains Prussian Blue, PB27. Natural Pigments and Golden have led the way in testing the lightfastness of this pigment. Some of Natural Pigments’ early/preliminary results showed that the lightfastness of PB27 may be especially affected by the use of various mixing whites. Prussian Blue may yield different lightfastness ratings when mixed with various white pigments. Please see the most current information. One resource is a video from Rublev/Natural Pigments which shows tests from their variety of Prussian Blue PB27 in various mixing whites. In this case the combination with white created different lightfastness ratings: https://www.youtube.com/live/xFn74zdaDHc?feature=share&t=1286.