Although iron is my trusty favourite mordant- easy to make, relatively low toxicity, and easy to dispose of- I have been experimenting with alum lately. My first results of eucalyptus on alum were not very promising. Fluro yellow is not my favourite colour. But then I tried double-mordanting, combining both iron and alum. I hoped that the saddening effect of iron would help tone down the brightness of the alum and bring in more subtleties. And it worked beautifully!
The alum has brought out these beautiful oranges and yellows from the eucalyptus leaves, while the iron gave more depth and detail:
The colours vary according to how much alum and iron are used, and the particularities of each piece of cotton too. It is important when eco-printing to be open to the different possibilities and to embrace the results you get. Each print is a gift from the leaves, so be grateful.
This onesie was bit of a failure originally. It had pale, faded grey prints, probably from not being scoured properly. The alum and iron mordanting prepared it well for a second round of eco-printing, and it was transformed into one of my favourite pieces so far. Aren’t the gumnuts exquisite?!
To do this double mordanting, I scoured the cotton, gave it a short dunk in one mordant, let it dry and cure, then dunked it in the other. Then I eco-printed the fabric in my usual way, using the instructions I share in my ebook Gum Leaf Alchemy.
If you’d like to learn more, I have a lesson about combining alum and iron mordants in my ecourse, Living Colour.