Using Invisible Ink

Summary: In our wildest spy fantasies, in addition to the any number of ruses employed by undercover agents, is the use of invisible ink to communicate covert messages in plain sight of the enemy. But while our part in the drama may be fantasy, the use of invisible ink - in a variety of forms - is very real; its uses ranging from the commonplace to the extraordinary. Invisible ink is used within the confines of any ordinary writing device. The message is written on ordinary paper; ...

In our wildest spy fantasies, in addition to the any number of ruses employed by undercover agents, is the use of invisible ink to communicate covert messages in plain sight of the enemy. But while our part in the drama may be fantasy, the use of invisible ink - in a variety of forms - is very real; its uses ranging from the commonplace to the extraordinary. Invisible ink is used within the confines of any ordinary writing device. The message is written on ordinary paper; once the ink dries it is no longer visible to the naked eye. The method used to make the message visible again depends on the type of invisible ink used at the start. These methods fall into several generally accepted varieties: The method that most people associate with invisible ink is that which is developed under the use of ultraviolet light. This can often be seen in the way of hand stamps used for readmission to amusement parks, night clubs, and the like. What is not visible to the naked eye suddenly glows under a UV light. Another type of invisible ink is acidic fluid of any type, such as wine, orange juice, or even milk. Once water is added, the fluid becomes a type of invisible ink that can not be seen under normal circumstances. Once heat is added, the writing will appear in a brownish color. Finally, there is invisible ink that can be seen by applying a chemical developer that has an acid base such as sodium carbonate, iodine solution, or silver nitrate. The actual ink can be anything from lemon juice to ammonia. Many people use invisible ink to mark belongings as a means of a theft deterrent. Upon the employment of any of the methods of invisible ink development, the item is immediately identified. The Internet can be a terrific resource for researching all the types of invisible ink and the methods used to develop it. You may be surprised by the number of household items used in such a non-traditional way.