So readers, after Monday’s feature From Flat to Round: Screen Printing Glaze Patterns onto Pottery, are you ready to try using foam to silk screen glaze onto pots? Well, as promised, today we are going to cover the steps in making a custom silk screen so you can be well on your way. Portland, Oregon, ceramic artist Brad Menninga explains the process below. -Jennifer Poellot Harnetty, editor.
The following instructions were excerpted from the January/February 2006 issue of Pottery Making Illustrated.
A silk-screen is a fine mesh of monofilament polyester fabric that pigments pass through, unless a masking material blocks it. One of the simplest ways to get pictures onto silk-screens is to use a light-sensitive photoemulsion. (Silk screening supplies can be easily found through an online search or at art supply stores).
To use, squeegee a thin, even coat onto a clean, dry silk-screen and allow to dry in a dark place. When dry, place a positive black-and-white or halftone image printed on a transparency onto the screen held in place by a clear piece of glass. Shine a bright light through the transparency, creating an exposure on the photoemulsion. Where the transparency is clear, light will pass through onto the light-sensitive emulsion, causing it to harden. Where the transparency is printed, the ink will block the light and the emulsion underneath will remain soft. When the exposure is complete, run water through the screen and the soft, unexposed areas will wash out. Exposure time depends on the type of emulsion used, the kind of light source, and the distance between the light and the screen.
Since the quality of the print will degrade at each step, start with a good print on the transparency. I prefer to use a computer with Photoshop software and print out the transparency myself. The advantage of using a computer is that you can easily resize, crop, increase contrast or otherwise alter the image. Converting the image to a halftone is also easy, and I can do color separation for multicolor printing.