Paper with invisible writing
Posted: Thu Sep 21, 2006 8:37 pm
A special paper could be produced that, when something is written on it with special ink with a pen, it initially appears to be invisible, but after connection of 6.3 or 12.3 voltage electricity the words become visible. Special eye glasses could be made to make the invisible writings visible. The writings could also be made sensitive to infrared light.
Reward: One for my self
Reward: One for my self