“I’ve been a wardrobe person for thirty years,” Cheryl says shaking her head, “and I’ve always thought that soda ash was an abrasive. Now I discover it’s a dye fixative.” Her mistake is understandable since soda ash or Sodium Carbonate, or for those of you who actually enjoyed high school chemistry, Na2CO3, is employed in a whole gamut of tasks from the manufacture of glass to the browning of German pretzels.
In simplest terms, it increases the PH level of your Procion MX fiber reactive dye, when working with natural fibers like cotton, silk and linen. The Soda Ash creates a permanent bond with the fabric; without it your garment will begin to fade with the first washing.
If you are using dyes like Rit or Tintex the solution will not be efficacious.
Detroit’s Glenda Hopp is a professional dyer and proprietor of So Many Colors, where she creates custom dyed clothing. She uses the low water immersion method of dying which employs a minimum of water and dye. We highly recommend Ms Hopp’s homemade videos presented on her website. She presents the technique simply and clearly.
The water, explains Ms Hopp, should be around body temperature. If the dyeing liquid is cold the dye won’t dissolve, if it is too hot it will clump. The goal is to have a Ph level of 11. As Ms Hopp points out, if you dissolve the dye in one container and add the Soda Ash in another the Ph should be around 13 or 14 because it will be diluted when combined with the dye. Obviously for optimal control this is a preferred method.
Ms Hopp uses Ph strips, which are available at Walgreens and other pharmacies. It appears that some wardrobe people simply eyeball it. You are looking for about four tablespoons per gallon. Being somewhat timid by nature I’d go for the strips, if not err on the side of more fixative.
You can add the Soda Ash mixture before you immerse the garment in the dye, during the process or after. If you are adding it after the dye, combine salt with the Soda Ash. Ms Hopp’s video has an excellent illustration of the different outcomes achieved depending upon when soda ash in introduced . It appears that adding it with the dye has the most uniform result and deepest color.
If you want a more worn look you may prefer to add it after you dye the garment and/or wash it once.
If you mix a larger quantity of soda ash than you need it will keep in a sealed container for several months. Once it is combined with the dye its’ effectiveness is gone after a couple of hours.
Just remember that, “Soda Ash is absolutely essential if you want your color to be permanent”, in Glenda Hopp’s words.