ROCHESTER, N.Y.--May 15, 2003-- Xerox Corporation scientists are demonstrating an experimental color printing technology today that allows them to print more than one image on top of another -- but view only one at a time by exposing it to a specific color of light. It is the first time that alternating high-quality printed color images have been displayed by controlling the light. Called "Switch-A-View" printing, the illuminant multiplexed imaging technology could allow companies to embed hidden pictures or messages in printed objects as commonplace as cereal boxes, T-shirts, coupons and standard printed documents. The technology, being shown at the Society for Imaging Science and Technology's PICS 2003 Conference here, was developed by Steven Harrington, Robert Loce, Gaurav Sharma, and Juliet Zhang, Xerox color scientists at the company's Webster, N.Y., research complex. Their technology turns conventional thinking upside down. The traditional challenge for color scientists is to design systems where the colors in printed images look the same whether they are viewed in incandescent or fluorescent light or by daylight. So Xerox researchers ordinarily seek ways to suppress variations in appearance. But this new technology is aimed at magnifying different responses to different light sources. The result: two entirely separate -- and quite detailed -- images can be printed on a single piece of paper, but only one of them will be seen under blue light, for example, and the other will be seen under red light. It's a more sophisticated version of the children's trick of using colored cellophane to reveal the "secret message." The scientists are able to create different effects with the hidden images, including 3D and simple animation. Their patent-pending technique depends on specialized color management software and switching back and forth between different light sources, and it requires the use of any calibrated printer and what scientists call "a characterized illuminant" -- light from a specific, narrow wavelength band. The technology grew out of the company's extensive investigations in color science, which account for nearly 40 percent of the Xerox research budget. "Multiplexed imaging technology is a form of extended imaging, or hyper imaging, where more information and value is contained in an image than what is immediately apparent upon the initial view," said Loce, who is a principal scientist in Xerox's Wilson Center for Research and Technology. "Xerox is investigating an array of 'hidden imagery' technology to enable today's documents to communicate in more sophisticated ways or offer new levels of security." DataGlyph technology, for example, encodes information in thousands of tiny diagonal lines, which can appear as a standard design element but actually contain directions for which envelope goes with which invoice or what type of stationery a document should be printed on. Another Xerox emerging technology can create hologram-like images, such as a watermark or official seal, that can only be viewed when tipping the document toward any light. Possible uses for the new Switch-A-View technology include security and authentication applications to foil potential counterfeiters, novelty images such as comic books or trading cards, and advertising. It could, for example, print multiplexed images onto cereal boxes, driving users to a designated Web site to view them under the correct light. Other possibilities would be T-shirts whose graphics are made visible in a club when a certain color light flashes, or popcorn boxes in movie theaters that suddenly display characters from coming attractions. Xerox has applied for patents on illuminant multiplexed imaging, and the technology is available for license. The PICS 2003 conference presents advances in image capture, image quality, image processing and imaging systems development. More than 10 Xerox scientists are on the PICS program, presenting papers, demonstrations and tutorials.