Prepare a design for silk screen printing. Try a design that can be printed in one ink color to start. Execute designs in word processing programs or graphics programs, using type and imported pictures or photos. More sophisticated designs can be prepared in graphics programs such as Adobe Photoshop and Adobe Illustrator, as these programs allow more flexibility in composing graphics using type and images. Many designs for silk-screen printing are prepared with black ink on white paper, then scanned into a graphics program where they can be used as a design element, or as the entire design. The completed design must be printed on a piece of clear vellum, also known as a film positive. An ink jet or laser jet printer is perfect, as long as it prints a very opaque layer of black ink.
Silk screens are made with a wood frame with synthetic screen mesh, stretched taut over it (silk is rarely used today). Buy pre-stretched silk-screen frames from screen print suppliers or art stores. Clean the screen with a degreaser and let dry. Coat the screen with light-sensitive photo emulsion and let dry overnight. Place the screen face down over a piece of foam rubber that fits inside the frame. Place the film positive face down on top of the screen. Place a piece of 1/4-inch heavy glass over the film positive and screen. Hang a halide light about 20 inches over the silk screen and turn on for five to 10 minutes (check the photo emulsion instructions for proper exposure time). Develop the image by spraying the silk screen with warm water in the image area. Blot with newsprint when done and let the screen dry.
Get a pair of screen print clamps and screw to a flat surface, such as a piece of board or plywood. Fit the silk screen frame with the image on it into the clamps and tighten. Check where the image falls when the screen is down, in the print position. Place newsprint or cheap paper under the silk screen and tape or spray glue into place. Add ink to the inside of the screen and pull over the image area with a squeegee. Lift the silk screen to check your result. If the print is clean, continue on to print your intended item. Multiple prints may be made.
If your silk screen washes out when you try to develop the image, lengthen your exposure time. If the silk screen will not develop and emulsion is stuck in the image area, shorten your exposure. The exposure time is critical in the silk-screen imaging procedure.
If your print is blurry, use a finer mesh screen with a higher mesh number, for example use 195 mesh rather than 80 mesh. Another option is to use thicker ink.
If your screen won't print, use a more open mesh or try thinning your ink.