1. Context

The history of colors and the history of chemistry merge in their origins. Along with fire and metallurgy, color is one of the oldest themes in chemistry. It's also one of the most studied, with major scientific, economic and cultural implications. Plant colors, which have contributed to a large part of France's and the world's economy and industrial heritage, had virtually fallen into disuse since the end of the 19th century.

Today, there is renewed interest in these products, fuelled by the depletion of natural oil reserves and a general awareness of the need to preserve our environment. The search for renewable resources and the growing use of natural materials show the public's interest in these products. In addition, growing regulatory pressure, public mistrust of chemically-synthesized products and the ban on certain synthetic colorants have led researchers...