A physical object is embedded with a first digital watermark component and a second digital watermark component. The first component is printed using a first ultraviolet (UV) ink. The first UV ink includes a first fluorescence decay time. The second component is printed using a second UV ink. The second ink includes a second fluorescence decay time, which is longer than the first decay time. The embedded media is illuminated with a UV pulse. The first component is detected after the first emission decay time, but before the second emission decay time.