Invisible Ink

Invisible ink, also known as security ink, is a substance used for writing, which is invisible either on application or soon thereafter, and which later on can be made visible by some means. Invisible ink is one form of steganography, and it has been used in espionage. Other uses include anti-counterfeiting, property marking, hand stamping for readmission, fun children's games, and marking for the purpose of identification in manufacturing.

Read more about Invisible Ink:  Application and Use, Properties of An "ideal" Invisible Ink, Screening Letters For Secret Messages, Invisible Ink Types, Modern Relevance of Invisible Ink Messages, Digital Invisible Ink

Famous quotes containing the words invisible and/or ink:

    The season developed and matured. Another year’s installment of flowers, leaves, nightingales, thrushes, finches, and such ephemeral creatures, took up their positions where only a year ago others had stood in their place when these were nothing more than germs and inorganic particles. Rays from the sunrise drew forth the buds and stretched them into long stalks, lifted up sap in noiseless streams, opened petals, and sucked out scents in invisible jets and breathings.
    Thomas Hardy (1840–1928)

    International business may conduct its operations with scraps of paper, but the ink it uses is human blood.
    Eric Ambler (b. 1909)