We get mordant questions all the time at Botanical Colors so why not create Mordant Monday??? Got mordanting questions? Email [email protected]
YOU ASKED: Should I mordant (alum is my go to) for your liquid dye indigo? I have read that it is not a needed step but also don’t want to dye without alum and make a big mistake. Hoping you can clarify please!!
KATHY ANSWERED: Thanks for your email and the question. The liquid indigo, also called Saxon Blue, was developed in the 1700s to dye wool. We recommend that you mordant and alum is perfect prior to dyeing, and you can also add a small amount of vinegar to the dye bath. It is true that you don’t necessarily need a mordant to dye with it but we’ve always gotten better results with it which is probably why you see both recommendations. Saxon Blue does not work on plant fibers, only animal fibers and works the best on wool.
Regular indigo requires making an indigo vat and does not require mordanting either, but the two dyes are not related except that they both are derived from indigo.
YOU ASKED: Loving MORDANT MONDAY! So how does one know when if a mordant bath is exhausted?
Obviously there are variables to consider, but assuming same WOF every time, what’s the estimated reuse limit? What would “multiple times” mean to ensure good results?
KATHY ANSWERED: Thanks for your email and I’m glad you like the info! I have a customer in California who reuses her mordant bath for wool mordanting at least 7 times.
I also have an analysis from long ago that shows that the initial alum take-up on wool is approximately 30%. So a 50% recharge seems like it would be completely sufficient to keep going for many baths. The signs that you might want to consider a fresh bath are that the alum bath liquid is getting gummy, super cloudy or you are seeing things like less saturated dye results for the same dye recipe and fiber. These are general guidelines and your results may vary depending on your water and the fibers you are mordanting.