The narrow violet cone of three-hundred-and-sixty-five-nanometer ultraviolet light lanced through the amber haze of Store #04.
Julian Vance did not lift either boot heel from the ribbed rubber anti-fatigue mat behind Register 1. He leaned forward across the scarred wood-grain laminate through the jagged aluminum sneeze-guard frame. He aimed the knurled black aluminum barrel of his counterfeit detector pen straight at the front plate-glass window and the overhead CCTV lens watching the vestibule.
“Mac, take two full steps back from that door frame,” Julian ordered, his voice cutting cleanly through the phantom warmth filling the aisles. “Do not touch the brass deadbolt, and do not let your boot touch the threshold mat.”
At Station 4, Marcus “Mac” Cole stepped backward across the drifts of white thermal audit tape. His hydraulic Route 04 ticket-punch forearm rose in a defensive guard as his breathing steadied. “I’m clear of the lock, Boss. Tell me what that purple light is showing you.”
“True solar daylight at sunrise carries between ten and forty watts per square meter of natural ultraviolet-A radiation,” Julian said, sweeping the tight violet beam horizontally across the interior face of the tempered windowpane. “Natural UV-A excites the trace iron and silica in commercial plate glass into a faint green fluorescence. Look at where my beam hits the window.”
