Invisible Ink Types
For practical reasons, the inks are listed here according to their method of development. It must be understood however that some inks - particularly those of organic origin or those consisting of a mixture of several chemicals - may be made visible by several methods. For example, invisible writing with soap water may be made visible either by heat, reaction with phenolphthalein, viewing under ultraviolet light, or by placing the page inside an iodine fume cupboard.
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Famous quotes containing the words invisible, ink and/or types:
“Fences, unlike punishments, clearly mark out the perimeters of any specified territory. Young children learn where it is permissible to play, because their backyard fence plainly outlines the safe area. They learn about the invisible fence that surrounds the stove, and that Grandma has an invisible barrier around her cabinet of antique teacups.”
—Jeanne Elium (20th century)
“International business may conduct its operations with scraps of paper, but the ink it uses is human blood.”
—Eric Ambler (b. 1909)
“The rank and file have let their servants become their masters and dictators.... Provision should be made in all union constitutions for the recall of leaders. Big salaries should not be paid. Career hunters should be driven out, as well as leaders who use labor for political ends. These types are menaces to the advancement of labor.”
—Mother Jones (1830–1930)