The earliest written description of the use of dyestuffs dates to 2600 BC and until the mid-19th century when William Henry Perkin invented the first synthetic dye, all dyes were derived from plants or animals.
I recently attended a workshop presented by Shanna Robinson, a professor at North Central Michigan College, on natural dyeing. We left the two hour class with a silk scarf, naturally dyed.
Most natural dyes need a mordant to fix the color to the fiber and increase lightfastness. Mordant literally means "to bite". The mordant is the chemical link that fixes the dye to a substrate by combining with the dye pigment to form an insoluble compound. Our scarf was saturated with three different mordants - ferrous acetate, titanium oxalate and a chalk solution. Each mordant produces a variant of the single dye color and even more variants were the mordants overlap.
Due to time constraints (each mordant must dry completely before applying the next), Shanna had applied two of the mordants and we added the last.
We prepared the dyes while the final mordant dried. Two dye bathes were prepped, one using coreopsis which will give yellows, oranges and browns, depending on mordants and the pH of the dye bath.
And a second with weld, which gives yellows.
The plant materials were weighed, added to water and allowed to simmer.
The plant materials were strained out.
And the scarves went in!
A good rinse at home, to remove excess dye:
Here's my coreopsis dyed scarf - it's pretty obvious that mordants have a huge influence on the final color!
The workshop was intended to be a brief overview of natural dyeing, not an intensive, "now you're an expert" experience and that goal was well fulfilled. I learned enough to be intrigued about the potential for using the techniques in my own fiber work - it's always great to add new possibilities!