We get mordant questions all the time at Botanical Colors so why not create Mordant Monday??? Got mordanting questions? Email [email protected]
YOU ASKED: I’m just trying out your new cold mordant aluminum triformate and have mordanted wool, bamboo and cotton After applying tannin to the cellulose I dropped it into the aluminum triformate together with the wool, and the water changed to green. I guess it’s due to the connection between tannin and aluminum? But am I doing something wrong and are the textiles fine for dyeing now?
I want to save the mordant bath for further use but now it has a suspicious color.
Also, if the natural dyes I am using contain enough tannin on their own, do I still mordant with aluminum sulfate before the dye bath? Or in this case, would I dye the fiber first with a tannin-rich bath, and then mordant with aluminum sulfate afterward?
KATHY ANSWERED: It should be fine, even if it has a tint. We had someone else say that the mordant bath turned a little gray and she changed the water source, but it should still be okay. We say give it a try!
YOU ASKED: I would like to use tannin and aluminum sulfate as my mordant for cellulose fibers. If I am using natural dyes with a high amount of tannin, do I need the tannin product as described in this article?
Also, if the natural dyes I am using contain enough tannin on their own, do I still mordant with aluminum sulfate before the dye bath? Or in this case, would I dye the fiber first with a tannin-rich bath, and then mordant with aluminum sulfate afterward?
KATHY ANSWERED: This is a great question. My understanding is that a pre-treatment with a tannin, then alum will generally increase light and washfastness for most dyes, including those that already contain tannin content. A good example is logwood. Logwood contains a lot of tannin but when used without a tannin pre-treatment and alum mordant, then lightfastness is poor, especially for cellulose. However, lightfastness and color yield improve with a tannin and alum mordant treatment. So if you plan to dye with only a tannin-rich material on cellulose, you might do the full pre-treatment, or try the alum post-dip and see which process works best for your practice.
Got mordanting questions? Email [email protected]