What is invisible black light chalk drawing?

In this fascinating medium, the invisible black light chalk appears white under normal light. However, each stick of chalk contains special (safe) chemicals that glow with a different color under black light.

The Method

Using a black light, a picture drawn with ‘invisible colored’ chalk on a white background. Since this chalk is white under normal light, the black light picture will be hidden or invisible. This hidden picture is used as a backdrop to a live drawing with regular colored chalk under normal light. Upon completion of the picture under normal light, lights are turned off (or dimmed slowly) so that the black light can reveal the ‘invisible’, hidden picture.

This first example, The Pilot, by Ding Teuling, demonstrates how effectively a picture can be hidden using black light chalk. The extraordinary effect of the gradual transition from the drawing viewed under normal light to the reveal of the hidden picture under black light can be dramatic. It is usually even more impressive in person. Each step in the gradual ‘reveal’ appears to be a picture all it own.

---

---

---

---

---