Glitter, pearlescent, fluorescent, thermochromic—even the names of specialty inks raise the specter of something exciting.

By Tom Polischuk

A close cousin to this color-shift effect can be obtained by metameric inks, notes Lorenz. With these inks, colors that appear the same under one set of lighting conditions can look much different when viewed under different lighting. He says that this can be used as a relatively inexpensive security feature.