Fig. 5From: Analytical characterization of 5,5′-dibromoindigo and its first discovery in a museum textileRaman spectral comparisons of a synthetic indigotin, b 6,6′-DBI from natural Tyrian purple, c the extracted dye crystals from yukata IMA 2015.112, and d 5,5′-DBI from Sigma. Peak wavenumbers are provided for the two isomers of DBIBack to article page