Bright Black was designed to demonstrate that a black card can look white, if lit brightly and surrounded by dark surfaces. The surface of the moon looks white when seen from Earth for similar reasons, and so this exhibit has emerged as a popular tool for teaching visual perception as well as some astronomy principles.

In the two images below, both taken of the of the moon, we can see that the surface is indeed very dark, in fact it's albedo is only 0.07.

Based on an idea brought to the w by Dr. Richard Brown by way of Dr. Alan Gilchrist, Bright Black was initially intended to be a demonstration carried out by museum staff. As an unmediated interactive it required a rather complex structure, where a user manipulates the cards at a distance using rotary solenoids.