DETROIT LOVES THE IDEA OF USING HOLOGRAMS TO TRY out future car designs. There's just one problem: Those ghostly vehicles, seemingly suspended in three-dimensional space, don't look precisely the same from every vertical viewing angle. A tall engineer perceives colors and shininess differently from a short engineer, who sees the hologram from a different angle. Auto makers can't make decisions about a car's design if they can't even agree what it would really look like.
American Propylaea Corp., which is located in Bir-mingham, Mich., thinks that it has the problem licked. In the past few weeks, Hans Bjelkhagen, the vice-president for research and development of the holography company, has developed a set of color emulsions that go onto the "holographic optical element"--the screen that produces the floating hologram when it's illuminated. The emulsions eliminate the color shift that's responsible for the variations when viewed from different vertical viewing angles, Bjelkhagen says.