Thermochromatic Ink
Security ink with a normal "trigger" temperature of 88 degrees F, which will either disappear or change colors when the ink is rubbed, usually by the fingertips.
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Famous quotes containing the word ink:
“Who does not see that I have taken a road along which I shall go, without stopping and without effort, as long as there is ink and paper in the world? I cannot keep a record of my life by my actions; fortune places them too low. I keep it by my thoughts.”
—Michel de Montaigne (1533–1592)