I recently purchased a towel with an interesting waffle texture. Unfortunately it only came in white, which I find a bit boring. We had an aging indigo vat sitting outside through some frosty nights and held some doubts whether it survived the weather. I also had a pile of rhubarb leaves leftover from a harvest. I had read that the leaves can act as a mordant and as a yellowish hue dye. The leaves aren’t edible due to their poisonous levels of oxalic acid and were otherwise destined for the compost bin. Rather than toss the indigo and rhubarb leaves, I thought to take a dip into the world of natural dyeing.
- Muddled the massive rhubarb leaves in a pot of water and simmered them for a half hour.
- Rinsed the towel, squeezed dry, and soaked the middle half of the towel in the rhubarb brew for a few minutes. Squeezed dry and set aside.
- Revived the indigo vat over the stove.
- Dipped the middle of each half side of the towel into the indigo vat then let it set in the air. This way the center of the towel would show the effect of only the rhubarb, to each side of center there would be indigo over rhubarb, followed by indigo only, and the ends would remain the plain white.
- Repeated a second dip into indigo.
The results show roughly 3 distinct colors. The original white ends, the rhubarb leaf dyed center is a dull yellow off white, and the indigo sections show no difference with or without rhubarb. The indigo parts ended up with a cloudy look which is due to the two indigo dips not completely overlapping. Overall this experiment helped build confidence that indigo keeps well over several weeks despite temperature fluctuations. The rhubarb leaves were a bit disappointing as I’m not fond of the color it set and it didn’t make much difference with indigo overdyed.
My last try at natural dyeing was with used espresso coffee grounds. They gave a dull brown tinge to a white tee shirt that was prepared with vinegar. That dull brown has lasted over many washes, but I wonder whether using rhubarb leaves as a mordant would have set it a darker brown. Something to try next time.