Weld, also known as dyer’s rocket or dyer’s weed, is a biennial plant widespread in Western and Southern Europe. Its use was very common in the dyeing industry due to its colorfastness, which earned it the title of “grand teint” (fast dye) in the 18th century. The coloring substance in weld is luteolin, a chemical compound from the flavonoid family present throughout the plant.
Its history dates back to the Middle Ages. The recipe for weld lake was already known to monk illuminators who used it to create their works.
This lake produces a very bright yellow with exceptional lightfastness.
The resulting yellow is the most brilliant, solid, and least likely to change when in contact with air and humidity, according to Jules Lefort in his book “The Chemistry of Colors.”
The process for making weld lake is similar to that used for madder lake.
Or cheesecloth
For your safety, it’s recommended to wear a mask and rubber gloves, and to work in a well-ventilated area—either outdoors or with the windows open and the kitchen extractor hood running—to avoid inhaling the fumes.
Monitor the temperature to prevent overheating, which could degrade the pigments.
Depending on the amount of lake formed, you may need to use an additional bottle with a funnel and coffee filter.
