Naphthol Green – a forgotten artists’ pigment of the early 20th century. History, chemistry and analytical identification

•Lakes of Naphthol Green B (Acid Green 1, Pigment Green 12, C.I. 10020) identified for the first time as artist's pigment in water and oil colours produced between 1910 and 1932.•Comprehensive source research on the dyestuff's and lake's history of production and fastness properties.•Reference data for its non-destructive or minimally-invasive analytical identification by Raman, SERS, FTIR, UV/VIS/NIR and XRF spectroscopy.