Medieval artists were as familiar with woad as today’s artists are with tubes of paint.  Woad, processed in large quantities for dying cloth, was an easy and relatively inexpensive blue pigment to manufacture, as the pigment was created from a by-product of the dye.  An illuminator who could not afford or find access to such sumptuous blue pigments as lapis lazuli or azurite would find woad an agreeable substitute.  An unscrupulous illuminator, who was contracted for a piece in which more expensive lapis or azurite was requested, might use woad instead, thus creating more income for himself.

Woad is a biennial plant, isatis tinctoria, and grows as well today in New York City as it did in medieval Britain, Europe, Asia, and North Africa.  However, there is little woad industry today.  The use of woad was first replaced by the more vibrant indigo, and now, natural dyes have largely been replaced by synthetic dyes.

Early Uses of Woad
Woad’s usefulness as a blue dye was discovered by the Picts, an early people of obscure origin who inhabited the present-day Scotland (noted on early maps as Pictland).  In the 9^th century, the Picts and the Scots joined.  The Picts were know to have tattooed themselves with designs, possibly of beasts.  They used woad for these unique tatoos, and their appearance is described by Caesar in his Commentaries on the Gallic War, as he writes: “All Britons stain themselves with woad, which forms a bluish color, and by this they are more frightful in appearance in battle.”(1)

The Economy of Woad
The making of a blue dye from woad plant became a profitable industry, and proliferated in the Middle Ages.  The many stages of making the dye and pigment employed several people, and certain towns were known for their woad production.  However, a better source of blue, indigo, was imported to Europe from the Far East and America in the late 16^th century, and the use of woad was slowly abandoned.  The indigo plant grown in Asia and America was cheaper than woad, and produced a more vibrant blue.  Thus, despite several efforts to ban indigo’s importation and use, the woad industry steadily declined.  Because of the significance of the woad industry, many areas suffered economically when it was supplanted by indigo.

The Effect of Woad on Land
Woad was especially harsh on land where it was grown.  It depleted the land of salts, and had other toxic effects on the soil.  Unfortunately for land owners, this reaction took place over a short period of time; woad used up the soil in 2 years.  After that time, the land was considered “woad sick”, and was not available for other corps until the soil recovered. Martin Luther observed to effects of woad on the land in the following: “Erfurt has been a very fruitful Bethlehem.  But the land has be ruined by woad, so that the blessing has turned into a curse.” (2)  Today, woad’s detrimental effects on the land have been noted, with woad referred to “weed called dyer’s woad”. Woad has been “infesting parts of the western U. S. with toxic arsenal against neighboring plants. [Woad] Is hard to eradicate and replaces grasses that are used fo animal forage.” (3) 

From Green Plant to Blue Dye: Making the Pigment