Basic Red 9 – fuchsine

It was the second synthetic dye material to be produced from coal-tar derivatives in 1856

Manufacturer/ product code:  euromex / PB 5305
Chemical Description:  synthetic aniline dyestuff
Color: red
Color Index: basic red 9
Date:  from 1859

Basic Red 9, commonly known as fuchsine or magenta, is a synthetic organic dye that played a pivotal role in the development of modern color chemistry. It was first synthesized in 1856 by François-Emmanuel Verguin during experiments with aniline derivatives, making it one of the earliest aniline dyes to achieve commercial success. Chemically, fuchsine is a mixture of closely related triphenylmethane compounds, typically present as hydrochloride or acetate salts, which give the dye its intense purplish-red color and high tinting strength.

Fuchsine is highly soluble in water and alcohol, a property that favored its widespread use in textiles, inks, printing, and early color photography, but limited its permanence in artistic applications. Its brilliant hue and low production cost led to rapid adoption in the second half of the 19th century, replacing more expensive natural red and purple dyes such as cochineal and madder lakes. In artworks, Basic Red 9 may be found in drawings, tinted papers, manuscripts, retouched photographs, and occasionally in paintings, often applied as a dye-based lake or in admixture with fillers.

From a conservation perspective, fuchsine is notoriously light-sensitive and chemically unstable. Exposure to light, heat, and oxidizing agents causes rapid fading, often shifting toward pale pink or complete discoloration. This vulnerability has made fuchsine an important marker of degradation in late 19th-century objects. Analytical identification typically relies on chromatographic and spectroscopic techniques, such as HPLC and Raman or UV–Vis spectroscopy, as its organic nature makes it invisible to elemental methods like XRF. Despite its poor permanence, fuchsine remains historically significant as a symbol of the transition from natural colorants to synthetic dyes and the birth of the modern chemical industry.