The refractive index of 19th-century paint media: a preliminary study

摘要: The feasibility of measuring refractive index (RI) on sub- milligram samples artists' paint was assessed. Medium-rich paint, glaze and varnish are suitable for such testing, their RI can be measured to ± 0. 005 in many cases. New thermally-aged 19th century oil/resin formulations gelled media were examined. It found that there no increase ageing, while the presence lead driers pigment had a significant effect both new aged material. Modern, unpigmented showed variously increased decreased after thermal ageing. expected from transparency oil as it ages not consistently paintings. Instead, independently analysed with high resinous rather comprising pure oil. seems depend its formulation more than age. observed hundred-year-old may due complex pigment-medium interactions, some at least involving compounds. -- CAL