Synthetic colorants, c 1900.

GERMANY - JULY 28: Six jars of synthetic colorants. Eosine 2Y manufactured by Chemische Fabriken vormals Weiler ter Meer, Uerdingen-am-Rhein, Germany; Rosinduline 2G by Kalle of Biebrich (merged with Wiesbaden in 1926); Brilliant Violet 49 by by G. Siegle & Co. of Stuttgart; Helvetia Green YYO by Society of Chemical Industry of Basle (Ciba); Victoria Brilliant Blue B by Farbwerke vormals Meister, Lucius & Brüning of Höchst-am-Main, Germany; Gold Orange by Friedrich Bayer of Elberfeld (and hence presumably before 1881). Eosin(e) is tetrabromofluorescein and was introduced by BASF in 1874; it is one of the most famous dyes associated with Heinrich Caro. Victoria Blue B was another dye made by Caro, for BASF, in 1883. Gold Orange (also called Orange II) was one of the earliest azo dyes. It was made by the German chemist Otto Witt for Williams, Thomas and Dower in 1876. Weiler ter Meer was founded by J. W. Weiler in 1861 and taken over by Edmund ter Meer in 1896. It became part of I.G. Farbenindustrie AG in 1925 and part of Farbenfabriken Bayer AG when it was refounded in 1951. Wilhelm Kalle set up his aniline factory in 1863 and it became a limited company in 1904, but the company was effectively taken over by Hoechst in 1908. Became a subsidiary of I.G. Farbenindustrie in 1925 and a subsidiary of the reformed Hoechst in 1952, but became independent again in 1997. In 1873 the Stuttgart firm Heinrich Siegle (was acquired by BASF. In 1889 Gustav Siegle (the son of Heinrich Siegle) bought the buildings back and started the production of mineral pigments and lacquers. The Gesellschaft für chemische industrie Basel (Society of Chemical Industry, Basle) was founded in 1884, but its dye production had begun in 1859. It was always known as Ciba which became the official name in 1945. (Photo by SSPL/Getty Images)