It is commonly taught that there are a finite number of pigment molecules in a dye bath, and adding water will not dilute them, because they will eventually bond to the fibers they come in contact with. Wanting to know first hand if this is true, I started the experiment.
I used a half ounce of Cortinarius semisanguineus (to one ounce of wool) which I extracted in 500ml of water. I contained the extraction in a half-gallon jar that was placed on a rack, submerged in a canning pot half filled with water. This double boiler method controls the heat and keeps the extraction process under 210° F.
After the mushrooms simmered at abot 195° F for about 45min I strained the mushrooms from the extract and divided it into 2 jars. The concentrated jar was diluted to 500ml to accomodate the wool, and the dilute jar was brought up to 1250ml using water that had been heated to the same temperature as the dye and wet wool. I added a half ounce skein of soaked and scoured wool to each jar and continued to simmer them for another 45 min.
Immediately the concentrated dye made its wool darker, it took 15 min for the dilute dye to look like it was going to fare well at all in this experiment, but I patiently waited. I was rooting for the dilute bath – as I have repeated this story as truth all these years. After 40 min, color change ceased, and at 45 min I removed them from the pot
Looking at the reddish skein on the left (in the middle below) and the rosy one on the right – there are definitely differences, but not sure if the dilution is to blame. Subtle temperature differences may have occurred because the concentrated dye bath was completely submerged in the double boiler water, while the water in the boiler only reached 800ml mark on the dilute jar. When tested both temperatures read about the same in the 190-195° F range.
Make your own conclusion and please share your comments or experiences below. I am definitely changing my lecture to say that dilution does matter, if for no other reason than temperature differences in the double boiler method.
Lesson of the day: Always question that which has not been proven.