The pots to the left have 5 ounces each of Angora(goat) roving in them. They also have 1/2 cup of white vinegar and water to cover them. The thermometer is to keep the temperature at the level needed to get the PH level to make the roving able to absorb the dye we will use and hold it for a 90 minute period to create a permanent color change.
The colander below holds a skein of yarn that has just been taken out of the pot in that it had its mordant set. Note that it is a brown tone and will be over dyed by this process. Meaning that the color will be a permanent change to another color. But remember these fibers and their color. So in the later photos you can appreciate the different colors they become. Influenced not only by the dye but the shade of color or in the case of the white roving no color at all. And a lot of natural dyes are enhanced by this and become more permanent using mordants. They help set the pigment improving color and light fastness.* The word comes from the Latin word "mordere" meaning "to bite". The ratio for a vinegar mordant is 1/2 cup of white vinegar for every 4 ounces of fiber with water to cover in an enamel or stainless steel pot over 160-180 degree heat for 60 - 90 minutes.
*Light fastness means when the yarn is finished with the entire process there is less chance of loss of depth of color to exposure of light over time.
The roving below is also Angora goat. It went home with me to get several serious rinses in cool water to remove almost all the excess color. All of the fiber involved also sat for 20 minutes or more before rinsing.
The roving will be washed with a fiber friendly product as I wasn't completed happy with the odor it retained after the process. Since the yarn skeins also retained the same odor I believe it is from the pokeberry plant itself. It wasn't an offensive odor just not pleasant to my way of sniffing.