The color rendering property of a lamp indicates how natural the colors of our surroundings appear under its light. If, for example, skin tones appear colorless, this is not due to the cool light color of a lamp, but rather to its poor color rendering. The color rendering index provides information about the quality of the lamp: Ra = 100 is optimal. For living spaces, at least Ra = 80 should be achieved. Halogen lamps achieve Ra = 100, energy-saving lamps generally achieve Ra = 80.