Reseda luteola is a plant species in the genus Reseda. Its common names include dyer’s rocket, dyer’s weed, weld and yellow weed.
Before the invention of stable synthetic dyes, this species was the most widely used source of the natural dye known as weld. The plant is rich in luteolin, a flavonoid which produces a bright yellow dye.
Analyzing a dye composition is the key to answer many questions during a restoration : it then tells us how it might have been and therefore how much the color faded, it helps creating an efficient work strategy and, sometimes, helps pinpoint the creation date and geographical origin of a piece.
Fun fact. Dye was one of the many ways artists used to obtain colors. For example, painters used to buy dyers used dye : precipitated with alkali, it separates pigment from aqueous solutions. It can then be used for oil paintings or watercolor.