FOR IMMEDIATE RELEASE
July 2004

Use of Radiometers Highly Encouraged for Optimum & Consistent Exposure, Concludes SPTF Research

FAIRFAX, VA - Members of the Specialty Graphic Imaging Association now have access to state-of-the-art research conducted by the Screen Printing Technical Foundation demonstrating how radiometers can be used to measure exposure light distribution, along with the effects certain variables have on that distribution.

These research findings, found in a special SPTF report entitled Testing Exposure Light Distribution, are available for download at http://www.sgia.org/sptf/public.html.

“Improper stencil exposure is one of the leading problems screen printers encounter today,” explains SPTF Technical Training Manager Dawn Hohl. “Incorrect or inconsistent exposure can create costly problems in production-including stencil breakdown on press, excessive pinholes, poor print quality, inaccurate image reproduction, and reclaiming difficulty.”

One important variable affecting exposure, the SPTF research found, is uniformity of light hitting the exposure area: Do the corners of a stencil receive the same intensity and quantity of light as the middle of the screen? If not - and if the difference is great enough - a stencil will have inconsistent properties in terms of durability and image reproduction.

Light distribution becomes even more critical when emulsion speed increases and/or emulsion thickness decreases.

High detail and halftone printing is especially impacted by (un)even exposure. The light profile is a result of the lamp type and configuration, lamp distance and placement, reflector design, and lamp age.

SPTF researchers measured UV light output across the exposure surface of several exposure systems. The industry’s research foundation recommends that a radiometer be used to measure the exposure area and get a true picture of the light distribution for a given set of conditions.

“Time spent improving or tuning an exposure system to make it consistent can easily return dividends of high quality and higher press efficiency,” states Hohl. “The cost of a radiometer and the time spent to do some simple testing will be quickly returned when fewer problems and screen remakes are experienced.”

For more information, please contact Dawn Hohl at Foundation headquarters.

SGIA (Specialty Graphic Imaging Association)
10015 Main Street
Fairfax, VA 22031-3489
Phone: 888.385.3588
Fax: 703.273.0456
E-Mail: dawn@sgia.org
Website URL: www.sgia.org/sptf/public.html