Yes, highlighter ink can glow, but not on its own in normal light. The glowing effect occurs under specific conditions.
The Science Behind the Glow
Highlighter ink contains special substances known as fluorescent chemicals. These chemicals have a unique property: when they are exposed to certain types of light, particularly ultraviolet (UV) light, they absorb this energy and then quickly re-emit it as visible light. This re-emitted light is what makes the ink appear to glow.
- Normal Light: Under regular room lighting (which contains very little UV light), the fluorescent effect is minimal or invisible. You see the color of the ink reflected, not the glow.
- Ultraviolet (UV) Light: When placed under a UV light source, commonly called a "black light," the ink absorbs the UV rays and emits visible light, causing it to brightly fluoresce or "glow."
As noted in reference information:
Since highlighters contain fluorescent chemicals, the marks made by highlighters will seem to eerily glow on their own when placed in a dark room with an ultraviolet light (e.g. a "black light").
When You Can See the Glow
You will most clearly observe highlighter ink glowing under these conditions:
- Presence of a UV Light Source: You need a black light.
- Dark Environment: A dark or dimly lit room enhances the visibility of the glow, making it appear much brighter compared to the surroundings.
Practical Applications
This property of highlighter ink is used in various ways:
- Security Markings: Invisible ink pens that contain fluorescent dyes can be used for security markings on documents or currency, only becoming visible under UV light.
- Art and Decoration: Fluorescent paints and inks are used in art installations, party decorations, and special effects.
- Inspection: Checking for fluorescent residues or marks in various industries.
In summary, while your highlighter marks won't spontaneously glow on your desk, they will come alive with an eerie glow when illuminated by ultraviolet light.
