I've been saving up my red onion skins and finally had enough to add them to the dye pot. I've been wanting to dye another scarf like the one I made last year, but was hoping this time for the khaki green that red onion skins can give.
And yay! I got it.
I haven't yet laundered and pressed them here in the photo, so they're deeper in color and much more wrinkly than they'll be later, but you can get the idea.
If you want to try getting these shades on fabric from your red onion skins, here's what I recommend. Simmer your onion skins in your non-reactive pot for about an hour or until the color has drained from the skins. Strain the skins out and add your pre-mordanted fiber. I use an alum mordant on the cotton fabric, simmer in the dye liquid for an hour then turn off the heat and let it sit overnight. The next day I pull the fabric out and let it dry before dipping it in an iron solution. You'll see the color start to change right away. I let it change for about a minute and then I rinse the iron solution off so it doesn't weaken the fibers. You can make the iron solution by soaking a steel wool pad in vinegar overnight, then removing the wool pad. The resulting liquid is your iron after-dip.
I dyed the floss with a slight modification. Instead of using alum as a mordant, I simmered the floss in a tannin solution then let it sit in soy milk overnight before rinsing it and adding it to the dyepot. I found that the floss took color up better than normal in this way. The orange is the color given just from the onion skins and the greens have been modified with iron.
Red onions are one of those dye stuffs that seems to be a bit fickle. Sometimes I get great color out of them and sometimes they're a bit lackluster. On the upside, they're generally easy to find and inexpensive. Worth a try. If you want to see some of the colors I've pulled from them before you can also have a look at this post.
Have you tried onion skin dye? What were your results?