Name: Deborah

Region: California

Message: When using thickened dyes (Procion with sodium alginate) must you use soda ash? Should you paint first then soak in soda ash? Can you soak first, dry the cloth, then paint it? Also, which is better for painting with thickened dyes, wet fabric or dry, or does it depend on what effect you're going for? I searched and only found that some put soda ash into the dye paint itself.

You must use soda ash, or another high-pH chemical such as sodium silicate, to set your Procion dyes, whether or not they are thickened with sodium alginate. However, you don't have to mix the soda ash with the dye.

You certainly can soak the fabric in soda ash and then line-dry it before painting it. I do not recommend using a clothes dryer to dry the fabric, because it's a bad idea to get soda ash into the dryer; it's a lot of trouble to clean the clothes dryer, but a residue of unrinsed soda ash in clothing can be irritating. Line-drying the soda ash in the fabric to be painted works very well.

Painting onto wet fabric is good for a watercolor effect. Painting on dry fabric is better if you want edges or fine details. You should try both to see what a difference it makes in the way the dye paint moves on the fabric.

It is very important, if you are painting soda-soaked fabric, whether wet or dry, to pour out just enough of your dye paint to use in half an hour or so. Your paintbrush, if you're using one, will carry enough soda ash back to your dye paint to make it start to react with the water. Expect this minute amount of soda ash to be sufficient to make the dye paint hydrolyze, or go bad, within less than an hour. Once this has occurred, the dye paint will not look any different, but the dye will lose its ability to bond to the fabric. If you are extremely strict about not allowing it to become contaminated with soda ash, your Procion MX dye stock solution should stay good for at least a week at room temperature, or longer in the refrigerator. Procion H dyes will last considerably longer in solution, but they must be steamed to set your painted dye design.
  
Your fabric should be made of a dyeable fiber, such as cotton, rayon (the viscose type of rayon), linen, or silk. Be sure it has not been treated to make it permanent-press or stain-resistant.

The two alternatives to presoaking your fabric are to add soda ash to your dye paint just before use, or else allow your unfixed dye painting to dry, and then paint over it with a sodium silicate solution. In each case, the soda ash or other high-pH chemical will activate the cellulose in the fabric so that it can react with the Procion dye.

For more information, see my page, "What is soda ash, and what's it used for in dyeing?".

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