| |
| |
Invisible ink - Wikipedia, the free encyclopedia |
 | | Invisible ink is applied to a writing surface with a fountain pen, toothpick or even a finger dipped in the liquid. |
 | | Telltale signs of invisible ink, such as pen scratches from a sharp pen, roughness or changed reflectivity of the paper (either more dull or more shiny, usually from using undiluted ink) can be obvious to a careful observer who simply makes use of strong light, a magnifying glass and their nose. |
 | | Invisible ink should not be used with glossy or very smooth paper types, since the sizing of these papers prevents ink from being absorbed deep into the paper and it is easily visible, especially when the paper is examined under glancing light. |
| en.wikipedia.org /wiki/Invisible_ink (1596 words) |
|