For any surface treatment with dye such as dye painting, stamping, stenciling, any kind of monoprinting, or deconstructed screen printing, I like to pre-treat my cloth in a soak of soda ash, also known as sodium carbonate, also known as fixer or activator in some circles. This prepares the molecules in the fabric with soda ash, so that I don’t have to add any extra liquid to my paint. The fabric is ready and waiting to activate the dye as soon as I apply it. A nice warm day is also good so that you can air dry your cloth outside on the clothesline. You can air dry it inside also; I just happen to like to hang it outside. Just don’t put it in the clothes dryer or iron it in any way, because it will turn brown….something about that high alkalinity…
I buy my soda ash/sodium carbonate at various places, such as pool suppliers, Walmart when they clearance the summer stuff, and Dick Blick. If I am at Festival or Paducah quilt show, I always purchase extra from Pro-Chem’s booth. I never have it shipped to me because of the weight. Of course now, I sell it when I vend at retail shows, so I order it from Jacquard.
My recipe is to use 1/2 cup of soda ash to every gallon of hot water. Several dyers I know call for 9 tablespoons, but 1/2 cup is 8 tablespoons and gives me a very high alkalinity, as evidenced by the ph tape in the picture below. I learned this from Robbi Eklow. Since I am usually preparing several yards of fabric at a time, I will mix two gallons of hot water with 1 cup of the soda ash in order to have plenty of solution. I use a 5 gallon laundry detergent bucket.
This is one of those cups that comes in every box of granular laundry detergent. I save them for measuring my dyeing supplies. The smaller one is 1/2 cup (I checked), so I quickly measure 1/2 cup of soda ash into my soaking bucket. Then using HOT water (so it dissolves), I stir with a wooden spoon which is reserved just for this task. My ph tape tells me the alkalinity is good, so my pre-soak is ready.
Now it’s time to soak. Since I purchase PFD (prepared for dyeing) cotton (so I don’t have to pre-wash), I immediately submerge my cloth in the bucket. I know some people go ahead and pre-wash their pfd to remove any oils or dirt. I have never pre-washed mine and have never had a problem with any of it (except there was that one time I got cloth that was marked PFD but it actually had sizing on it…and there was a couple of bolts that even pre-washing didn’t make a difference…that’s a whole horror story all by itself). One little trick I’ve learned since I’ve been doing this for awhile is this: if you find the fabric wants to float in the bucket and not submerge and immediately get wet while you are pushing it down in the water, there IS sizing on it and you should pre-wash it, while hoping it’s not a permanent press finish, because if it is, you won’t get anything other than a pastel color on it. This means it is even resisting the water, which spells trouble.
Soak it 20 minutes or longer, which will not hurt the cloth. Using latex, vinyl or rubber gloves, wring the pieces out and give the cloth a spin in the washer spin cycle. Make sure it doesn’t rinse at all, or you will have to soak again. You don’t want the washer to rinse out your soda ash. Hang on the line to dry, then fold up and keep separate from your other cloth. It may be helpful to mark it in some way. You can keep it this way for a fairly long time before using. Leftover soda ash solution can be saved for a long time and re-used, so don’t throw that away.
I probably should clarify that these are soaking instructions for cotton only! For silk, you can use soda ash or white vinegar for the pre-soak. My experience has been that you will get different colors depending on what the pre-soak is. It’s an interesting side effect. Silk cannot have soda ash on it for very long without affecting it adversely. I do not soak silk in soda ash and leave it. I usually treat silk with white vinegar.