A patterned indicator is provided which contains latent information. The patterned indicator includes a first substrate having first and second surfaces, the first surface having a uniform pattern printed of an ink thereon. A second transparent substrate having first and second surfaces is also provided. An adhesive activator is provided on the first surface of the second substrate. The indicator is activated by placement of the first surfaces of the first and second substrates into adhesive contact such that the ink and adhesive activator coact to cause the ink pattern to gradually bleed and blend together to cause a change visually perceptible through the transparent substrate in a selected time interval.
A preferred embodiment of the invention is a parking permit, while other preferred embodiments include transit tickets, admission tickets, time passage indicators for other applications. Also within the scope of this invention are patterned indicators printed with inks having multiple sensitivities for indicating tampering with goods in packages sealed with such indicators.