To Paint Pigments
Some Important Dyes
- Both of the following dyes were sold in powder form
and then mordanted with alum to form a lake.
- There are three methods of mordanting:
Pre-mordanting Treat the material with the mordant, then
apply the dye.
Meta-mordanting Add the mordant to the dye bath.
Post-mordanting The dyed material is treated with the
Rose Madder (Red)
- Made from the
roots of the
common madder plant (Rubia Tinctoria)
- Produces a bright red color:
- Many civilizations have used rose madder, going back to
Ancient Egypt and India, to produce rose-colored natural dyes.
- The color index name used by paint and textile chemists is
Natural Red 9 (NR9).
- Was not used as a paint pigment in the Renaissance because it
was considered a weak color.
- In the 19th century, a synthetic form of Rose Madder, called Alizarin
Crimson, was invented that was superior.
- Made from the leaves and stems of the
woad plant (Isatis Tinctoria)
- The pigment in woad is the same pigment as that in indigo, although it
is less concentrated.
- Woad was the only source of blue dye until the end of the 16th century.
- Julius Caesar reports in De Bello Gallico that the Britians
colored their bodies with woad blue. They were known as the
- A woad based pigment was used to illuminate the
- For a time in the 12th century, the official color of royal robes
in France was changed from cochineal red to woad blue. This greatly
increased the demand for woad.
- Indigo dye has a distictive blue color.
- Obtained from a variety of sources, the primary commercial
plant in Asia being
- Amoung the oldest dyes for textiles and printing.
- Was a luxury item imported from India by Arab merchants.
- Used in Ancient India, Mesopotamia, Egypt, Greece, Rome, Britian,
and South America.
- Was a rare commodity in Europe during the Middle Ages; woad was
- In the late 15th century, increased global trade brought in indigo
from India and South America.
- Since indigo was a superior die to woad, it threatened the woad
- France and Germany outlawed indigo in the 16th century to
protect the local woad industry.