Replacing Indigo by Blue Starch extracted from Woad (Isatis Tinctoria)

Indigo manufactory: range of basins in which indigo was extracted (Histoire générale des Antilles, 1667).[/caption]

On October 21st, 1806, Napoleon had decreed the Continental System, a measure taken to deprive England of any contact with the continent. For this reason some products were missing, such as indigo, a blue dye. The government suggested to replace it by the blue starch extracted from woad. Blue dye can be obtained from its leaves. In 1811, the government opened a competition to develop woad cultivation. According to Nicéphore:

Pastel des teinturiers (Isatis tinctoria) Woad (Isatis tinctoria) © Matt Lavin

“I read with interest M. M. Niépce-Barrault’s observations, which you sent me on November 28th on the most convenient time to harvest the woad leaves, and about the means to extract the dyeing starch without the intervention of any precipitating agent; they are, as you put it so well, a new proof of the sagacity and zeal that animate them. Please let them know that I am transmitting those to the commission responsible for examining everything pertaining to the subject, done in different locations, and to notify who is is the most apt to define the theory of the fabrication of indigo-woad, so as to improve its practice.”
Answer from the Interior Minister. December 7th, 1811

The competion launched by the government did not bring any promising results. In 1813, however, they decided to rekindle an interest in woad cultivation and indigo extraction by giving subsidies: three to five francs according to quality, under the condition to produce at least fifty kilograms of indigo per annum. The prefet himself on 24th April 1813 incited the Niépce brothers to start all over again on this project. Woad cultivation restarted in Saint-Loup de Varennes. Fifty-six years later, in 1867, a historian named Fouque witnessed: “{…} Woad-Indigo cultivation, we saw it, has left many traces in what used to the beautiful Niépce property, in Gras,the bourough of Saint-Loup de Varennes. The garden of this family property, the fields, even the ditches of the main road, spreading on many kilometers have woad plants {…} that naturally reproduce without any cultivation for more than half a century.”

The year 1812 saw the decline of the Empire. It collapsed putting an end to the Continental System. Woad cultivation became useless.