A highlighter is a felt-tip pen filled with transparent fluorescent ink. The first highlighter was introduced in 1963 by Carter's Ink Company, using the trademarked name Hi-Liter. Avery Dennison Corporation now owns the brand, having acquired Carter's Ink Company in 1975.
Many highlighters come in bright, often fluorescent colours. Being fluorescent, highlighter ink glows under black light. The most common colour for highlighters is yellow, but they are also found in orange, red, pink, purple, blue, and green varieties. Some yellow highlighters may look greenish in colour to the naked eye. Yellow is the preferred color to use when making a photocopy as it will not produce a shadow on the copy. Yet, the use of different colour highlighters simultaneously can systematically make information even more organized and readable.
Highlighters are available in multiple forms, including some that have a retractable felt tip or an eraser on the end opposite the felt. Other types of highlighters include the trilighter, a triangularly-shaped pen with a different-coloured tip at each corner, and ones that are stackable. There are also some forms of highlighters that have a wax-like quality similar to an oil pastel.
"Dry highlighters" (occasionally called "dry line highlighters") have an applicator that applies a thin strip of highlighter tape (physically similar to audio tape) instead of a felt tip. Unlike standard highlighters, they are easily erasable. They are different from "dry mark highlighters", which are sometimes advertised as being useful for highlighting books with thin pages.
Example of highlighting on a word processor.
- Sanitization (classified information)—using black "highlighter" to hide classified information.
- WO 2005042654, Schmid, Christian; John L. Stoffel & Bill Sperry, "Ink compositions for use in highlighter markers and associated methods", published 12 May 2005
- Hilary, Greenbaum; Rubinstein, Dana (2012-01-20). "WHO MADE THAT? The Hand-Held Highlighter". The New York Times Sunday Magazine. p. MM20. Retrieved 2012-01-26.
- Highlighter Ink Glowing Under a Black Light
- Media related to Highlighters at Wikimedia Commons
- The dictionary definition of highlighter at Wiktionary