Lighting: CRIs

CRI describes how many colors are present in the lamp, and therefore visible in the room; color temperature describes how yellow or white the lamp looks when stared at.

Incandescents and halogens are inefficient and create a lot of heat but have high CRI; fluorescent lamps require a ballast and are more efficient but have a lower CRI and don’t work well in cold temperatures; high-pressure sodium, metal halide, and mercury vapor lamps also require a ballast and are efficient. They have lower CRIs and take a while to warm up.

LEDs are efficient and last a long time, but need to be kept cool and require a driver.