Why is a candle flame yellow?

The perceived color of an object is determined by the spectrum (SPD) of its radiant flux factored by the luminous efficacy of the human eye.

If the human eye responded equally to all wavelengths in the visible range, the candle flame would appear red. But since the eye sensitivity peaks in the green and diminishes toward the red wavelengths, the eye perceives the color as yellow.

Color puzzles

Vision concepts

Color vision concepts
  HyperPhysics***** Light and Vision Go Back