Natural dyes have been used since the beginning of organized society, developed so humans could paint their bodies, clothes, houses, weapons and religious icons. The colors were obtained from plants, animals, fruits and earth. In Mexico, they include indigo, cochineal (the bug parasite of the prickly pear cactus paddle), moss, nut shells and leaves, wild flowers, tree bark, and even a sea snail that emits a deep purple ink. Natural dyes are scarce, higher priced, and require a monch longer, more complex process to produce.
For example, to make red using cochineal requires one day to grind the grain of the cochineal bug (cultivated on the cactus for three months), one day to prepare the wool, one day to mordant the wool, and one day to dye the wool. This does not factor in the three-to-six months of time required to “grow” the bug on the cactus.
To produce a synthetic red dye takes one day. Color variation and intensity is controlled by adding more dye to the solution. It is not the complex chemistry that is involved in the natural dyeing process.
My friend Eric Chavez Santiago, director of education at the Museo Textil de Oaxaca, says that he has experimented with formulas using cochineal and a variety of acids and bases, including ash and lime juice. “I’ve been able to document over 100 different colors using cochineal, shades ranging from pink to red to purple to orange.” With a synthetic dye, one flat, consistent shade is standard.
Intensity and Brilliance
Natural dye color variation and brillance is achieved by mixing different mordants with one batch of skeins, manipulating the PH of the dye baths, investing hours of time for one color. Colors obtained from natural sources tend to be earthy and subtle. Synthetic dyes often produce garish, stark or muddy colors. Wool rugs prepared with natural dyes are colorfast and will last a lifetime. Colorfastness can be tested by rubbing the surface of the weaving (if the weaver lets you) with a damp cloth. If the dye does not transfer, there is a good chance that the color is permanent.
The Price Difference
Natural dye materials are scarce and expensive. For example, cochineal is more costly per ounce than gold. Synthetic dyes are readily available at low cost, resulting in a less costly rug to produce. Density of weave also adds to quality and therefore to cost. A low cost rug will likely be woven with synthetic dyes, on brittle, machine spun (not hand-spun) wool, and have a looser weave.
Health and Wellness
The chemical fumes that are breathed in from the vapors of the dye pot are toxic. Sulfuric acid is potent and can burn the skin. If it splashes into the eye a person can go blind. Because people dye at home and there are not regulations around the use of chemical dyes, most people don’t take necessary precautions to use a face mask. As a result, over time many develop respiratory problems and lung cancer. A movement toward the use of natural dyes is also a good public health step. If you buy a rug dyed with natural materials, even though it may be more expensive, you know you are making a difference for a healthier life.
We encourage you to be informed, know your rug weaver, and ask to see the dye pots (not just a demonstration of lime juice squeezed into the palm to dilute a few grains of cochineal). Know before you buy.