Many highlighters have bright and fluorescent colors, and will emit fluorescent colors under the night light. The most common color is yellow, and other colors include pink, blue, green, orange and purple.

In addition, there is a dry fluorescent pen, which has no felt tip, but has a special opening to stick the fluorescent strip in the pen to the document, just like a tape. This kind of fluorescent pen is not as easy to clear as the traditional one.

The fluorescent pen has fluorescent agent. When it encounters ultraviolet light (sunlight, fluorescent lamp, mercury lamp are more), it will produce fluorescent effect and emit white light, which makes the color look dazzling fluorescent. Now there are also colorless fluorescent pens that can be hidden. There is no color after writing, and the written content can be displayed after being illuminated by the purple light behind the pen.