Sodium Alginate is a pure type of dried, ground kelp (seaweed) used to thicken dyes and paints.
When added to dyes, the dyes become more the consistency of paint. You can then brush the dyes on and they will stay put. Also use for stamping, stenciling or silk screening the dyes.
Sodium alginate can also be used as a resist when using the gutta serti technique. Thin it to a workable consistency, color it with dye, if preferred, and after steaming, it washes out and leaves the color behind.
Using Sodium Alginate as a Resist on a Scarf
- Mix sodium alginate according to directions on the package a day before painting so it will thicken.
- Choose the silk fabric or a garment you wish to paint; you can leave the silk white (or its original color), or paint light shades of dye on it, overall, or leaving some white spaces.
- Crunch a plastic bag into a ball and form a “handle” with part of it, securing with tape or string; it will resemble a plastic flower bouquet with a stem.
- Dip crumpled plastic into the sodium alginate, then dabble it all over the silk, creating whatever pattern you choose; the plastic produces multiple edges and the sodium alginate acts as an excellent non-line resist. Or, brush on the sodium alginate.
- While sodium alginate is still wet and you can see it on your silk (sodium alginate dries clear and difficult to see), apply dyes around the sodium alginate in your own way (brush, sponge, spray, drip), then use salt crystals to add texture to the wet dyes on the silk.
- Let the entire piece dry completely, then dabble more sodium alginate over areas of color and/or texture you like best on your silk.
- For a second time, while the sodium alginate is still wet and protecting those areas, apply more dyes around the sodium alginate, and more salt on the wet dyes, to create your own layered, textured patterns on the silk.
(Information above drawn from instructional notes by Becky Kyhl, Iowa, 2012)
(See Dye Thickener in Techniques section.)
Using sodium alginate as a resist by Becky Kyhl