Why do colors illuminated with moonlight lack color?

Asked by: Amanda Bond

Thus, the low light conditions of night vision usually do not stimulate cones, and all we are left with is a colorless perception of the world around us.

Answered by: Rob Landolfi, Science Teacher, Washington, DC


The primary reason is due to the way our vision system is designed. Our eyes are a high-resolution color sensing system with a wide dynamic range. This means we can see a broad range of colors and sharply resolve images with a wide variation in brightness - a miraculous combination.

The parts of our eyes that are sensitive to color are called cones. They function primarily in the bright sunlight and work like a three color image scanner. The parts of our eyes that provide high resolution and sensitivity to a wide range of intensity or brightness are called cones.

Our color-sensing rods require a high level of illumination to function properly. Cones, that can discern shapes and texture in very low light levels, are not sensitive to color.

Even though there are colors reflected from objects illuminated by moonlight, they are just too dim to activate our color vision.

See http://www.photo.net/photo/edscott/vis00010.htm for a detailed explanation of human vision (in color).

Answered by: Scott Wilber, President, ComScire - Quantum World Corporation