The present invention provides inexpensively an article with a hard coat excellent in anti-staining property, lubricity, scratch resistance and abrasion resistance. The yield stress fluid is capable of suspending insoluble materials in the form of particulates andor droplets requiring suspension or stabilization. A first and a second channel signal are derived as a function of the sets of sensor signals in a processing device via a first and a second combination device. The dials bear indicia indicative of the time and date that the sheet of M8 chemical detection paper was last inspected.