Decorative formliners for sound wall construction is the technique Spears chose for demonstration at the Artistry Demo. The technology for the urethane formliners he used starts by scanning photos and graphics into a computer and transferring the files to a computer numerical control router that travels in a straight line, raising and lowering a router bit over the urethane. The changing width of the line causes shadows to appear in reflected light that presents the image—when there are no shadows no image appears, you only see the cut lines.
Spears brought two panels to show visitors what a finished project looks like—these included a photo of Marilyn Monroe and an image of the Three Stooges. At the demo, he formed around the formliners and placed concrete, being careful to remove entrapped air with internal vibrators. When the castings were demolded the following morning, the concrete images were revealed. His concrete was a natural color but the appearance can be enhanced with either integral colors or colored sealers afterward.
View more of the best in decorative concrete from the 2009 artistry demos at the World of Concrete.