Sherwood Green, A Citric Dye
We will talk about what we don't see—this citric-dyed Sherwood Green yarn, available from the Sport Yarn Store, and most other hand-dyed yarn, is not level in dyer's parlance, which means it doesn't have an evenness of color. We like what we don't see.
Notice the color variation along the length of the yarn: there are several colors of green depending on how the blue or the yellow (blue + yellow = green) took. A lime green color evidences more yellow dye while a sea green color evidences a predominance of blue dye. And there is a red-brownishness to certain portions of the yarn where the red dye overwhelmed the blue and the yellow dyes tending toward brown. (green + red = brown).
We usually mix three colors to get a hue; the two primaries or a secondary give us the basic shade and the third color is a complement (the red here) to the first two that tones them down. We try to make a color story that is keyed to the lovely muteness and harmony of natural colors.
And we aim for an absence of levelness. How we do that is to add the weighed dyes and the citric acid to the cool water, along with the yarn to be dyed, in the pot and take the temperature slowly up to about 175F and beyond. The dyes strike (more dyer's parlance: realize the color) at different temperatures, each color should have its own temperature.
Dye houses are formulaic; they have a simple recipe for the levelness of color of yarn and that would be to heat the water and when it reaches 175F, add the dye, add the citric acid, add the yarn then check it with at pH meter.
This unevenness gives a rich texture to the knitted garment in the play of colors along the strand of the yarn.