The pigments lightfastness research analysis

Inorganic pigment in the sun for a long time,the color will darken. Researchers think that this phenomenon may be due to chemical reaction,or for pigment crystal shape change.Lithopone dims in the sunshine,because the zinc sulfide reduce to metal zinc;After exposure, dark grey disappear,metal zinc can be formed zinc oxide.Test prove that when lithopone be after exposure,the content of zinc oxide increases.

zinc oxide content increase.When chrome yellow be exposed,due to reduction action,to generate lead chromate,therefore,lead to a darker color.

By Nicole