Samples of dyed wool, c 1910.

Samples of dyed wool, c 1910.

Samples of dyed wool, c 1910.

Original dyestuffs prepared by August Wilhelm Hofmann, 1858-1863.

The Perkin dyestuffs factory at Greenford Green, Middlesex, c 1870.

Heinrich Caro, German chemist, late 19th-early 20th century.

Peter Greis, German industrial chemist, mid 19th century.

Sample of picric acid, (2,4,6-trinitrophenol), late 20th century.

Carl von Graebe, German organic chemist, early 20th century.

John Mills, Jean Simmons and Harold Wilson, 1948.

Thomas Dix Perkin, brother of Sir William Henry Perkin, 1867.

Sir William Henry Perkin, English chemist, with colleagues, c 1870.