One of the most interesting ways that I've found to use a thermofax screen is to make multicolored images using water-soluble crayons, such as Caran D'Ache. I find these colorful one-of-a-kind prints both versatile and appealing, whether used on their own or in combination with other screen-printed fabrics. The pomegranate above is a simple example of the technique -- with both the red fruit and the green leaves printed at the same time.
The process depends on using a polymer based medium to carry the water-soluble pigment onto the fabric and, in drying, to bind the image to the cloth surface -- after appropriate heat- or time-setting. I've used various kinds of polymer media with the process -- transparent fabric screen ink "extender," Golden® or other brands of gel medium, both glossy and matt, and the newer Golden® open medium, which does not dry as quickly in the screen as the straight acrylic mediums do.
Essentially, one colors the open areas of the thermofax (this works with traditional screens, as well) with the water soluble crayons, coat the screen with a generous portion of medium, letting it sit a SHORT time, then screen-printing as usual (a plastic scraper works better, I think, than a foam roller). The first print is often partial or broken in line, since the crayon can act as a partial resist in the screen, the second and third are usually quite interesting; the color starts to fade and blend with the subsequent prints. I often recolor the screen without cleaning it, working quickly to beat the drying process, and that can lead to interesting results, as well.
Because you are using a relatively heavy medium, this process is best for substantial fabrics and for usages where some change of hand won't be disturbing or distracting to your end result. It doesn't work well on silk scarves for example, but is great for art quilt and mixed media work.
Coming up this fall, I'll be teaching a full-day workshop on this technique at the International Quilt Festival in Houston, Thursday, Oct. 15 in the Mixed Media classroom and I'll be demonstrating the process at one of the Mixed Media Miscellany samplers, Saturday, 10-noon. There will be lots of different polymer media to try out, some different kinds of crayons to test, hints for the best designs and lots of demo and hands-on explorations. For more information, see www.quilts.com.
