The world of natural dyeing, like a good piece of music, is full of nuance and detail. Water, soil in which the dye plants grew, weather, concentrations, duration, ratios, temperatures, mordants, fibers, over-dyeing, pre-mixing of dyes, double or triple mordanting, modifiers, and a host of other factors that I am aware of or not are the individual notes that play into the final expression, the color.
Pictured above is my little piano on which I try to isolate these individual notes. The right hand section of it is dedicated to my pH level experiments ran at the end of April and beginning of May. After experimenting with about 50 Indian dyes I settled on a dozen or so and tested them at pH levels ranging from 4 to about 8....
A word of caution here. Personally I am not a great fan of measures and instruments, feeling that they separate me from the materials themselves, and use tools such as a scale, thermometer, litmus paper, etc. sparingly. In other words, the 4 to 8 pH is only theoretical. The middle line is neutral pH, not 7, but rather the pH of the dye bath without any modifiers. Going from the center to the left you will find progressive lower pH levels and to the right higher.
...and finally the pictures themselves of some selected Indian dyes..They speak for themselves so I will refrain from over commenting and save it for another occasion. Each line is composed of seven samples, in the order of: 1. unmordanted, 2. Al, 3. Fe, 4. Cu, 5. Sn, 6. Cr and 7. Z. All the samples have been light tested for 4 to 6 weeks, and as in all recent experiments it is an angora/merino blend....
1. Madder. I use two species of madder. Iranian and Indian, and they are pictured in that order.
2. Ravanchini or some form of Himalayan Rhubarb. Still not sure of which exact plant this is, but it is a great dye.
3. Patang or some form of Indian Logwood
4. Tesu or Butea
7. Daru Harydra or Berberis
The story is the same for my other 8 dyes....Every mordant, every dye, and every color is to one degree or another pH dependent.