CHARACTERIZATION OF SILK-COTTON AND WOOL-COTTON BLENDS PATTERN BOOKS BY FIBER OPTICS REFLECTANCE SPECTROSCOPY. THE BOOMING MARKET OF FIRST SYNTHETIC TEXTILE DYES IN EARLY 20th CENTURY

•Early 20th century azo synthetic textiles dyes were analyzed with FORS.•Molecular structures of almost all of the analyzed dyes were found.•Dyes color coordinates and FORS features were treated by PCA and PLS-DA.•A reference dataset for researches on early 20th century synthetic dyes was created.