The color rendering index (CRI) is a measure of a light source's ability to reveal the colors of various objects faithfully in comparison with a natural light source. Electric lights with a high CRI are effective in improving the perception of space by ensuring that colors are seen more accurately and vibrantly. This can have a significant impact on the aesthetics of the environment, as well as on the well-being and productivity of the occupants, making high CRI lighting a preferred choice in design according to the WELL Building Standard.