August 01, 2005

The technique of printing a thin layer of ink (usually white) on a garment is called underbasing. The underbase blocks out the color of the garment, serving to brighten the colors printed on top. The brightness of the overprinted color(s) can be varied by breaking up the underbase into different percentage halftones.

To see this concept in action, print a layer of white plastisol ink that is divided into 20%, 40%, 50%, and 90% halftone areas, and flash it. Then print a solid block of teal-over-white pattern. You'll end up with 10 shades of teal, including the one printed directly on the dark background. By printing teal over varying percentages of halftones, you're essentially getting 10 "free" colors.

For underbase design elements that need to stand out with a 90% halftone, use a 20% to 30% halftone underbase to achieve a more subtle effect. Remember, though, when using this technique, you may be printing plastisol on fabric as well as ink.

For optimum results, it's important to use a semi-translucent plastisol. A plastisol that's too opaque covers the underbase too well and does not permit the underbase's graduated tonal areas to show through. Semi-translucent plastisols also allow you to print colors on top of colors to create secondary and tertiary hues. — IMPRESSIONS Archives