How to Turn Your Phone’s Camera Flash into a Black Light
Black lights (long wave ultraviolet light) aren’t the most useful of things in everyday situations, but when the occasion does arise (secret messages, etc.), this nifty tutorial will definitely come in handy. Simply put, all you need is some tape and Sharpie markers. One of the innovations for night and all-weather flying used by the US, UK, Japan and Germany during World War II was the use of UV interior lighting to illuminate the instrument panel, giving a safer alternative to the radium-painted instrument faces and pointers, and an intensity that could be varied easily and without visible illumination that would give away an aircraft’s position.