Mordanting Cotton First we’ll deal with mordanting cotton because the options are limited. Usually cotton is mordanted with alum. Sometimes iron is used to create darker, sadder colors. Care has to be taken with iron since too much can cause the fiber to deteriorate.  Most dyers feel both alum and iron are safe mordants—but like any powder to do with dyeing you do not want to inhale it, injest it,  or get it on your skin. Painting stores have relatively cheap air filter masks used by house painters. Sometimes I just use a medical dust mask, but I really like the air filter one better. 

There are two methods for mordanting cotton: (1)the alum acetate method and (2)the alum sulfate (normal dyers alum) and tannic acid method. Alum acetate is a more expensive alum that is only available from speciality suppliers. I prefer it to the alum tannic acid method which is cheaper but multiple step and takes significantly longer. For alum acetate, use 5% WOG or 4 Tablespoons for 1 pound. Use 1/3 cup for 1.5 pound. Dissolve alum acetate in boiling water. Hold at 100 degrees for at least one hour and longer will not hurt it. Drain water (do not rinse). Either keep goods in plastic if going to dye right away or dry and use it later. If dry, soak in water before dyeing.

Only a portion of the alum will be soaked up by the goods. If you want to mordant more goods, just put in ½ as much mordant. After 2-3 uses, go back to the full amount of mordant and start again but you can continue to use the same water.

Another option is a 3 step mordanting process using potassium alum sulfate (common dyers alum) and tannic acid. To do this mix ½ cup alum sulfate in 4 gallons of hot water in a plastic bucket. Make a tannic acid solution by dissolving 2 tablespoons in 4 gallons of hot water and put in a separate bucket. Put scoured wet cotton fabric or yarn in the alum sulfate mixture for 12-24 hours, then rinse. Then put fabric in tannic acid solution for 12-24 hours. Rinse again. Put back in alum solution for 12-24 hours. You can reuse these alum and tannic acid mixtures several times. Sumac is a source of tannic acid.

I've had lots of fun teaching quilters to natural dye. Quilting is something I wish I had the time for but that yarn and fleece calls me too much.  The fabric above or some like it, is headed to a patchwork lining on my natural colored circular sampler bag.  Now if I can just figure out what sort of interfacing to apply and how to make a bag lining, I'll be set.  I sure wish I'd paid more attention when Mom tried to teach me to sew.  Linda