In video production, a means of combining video images by replacing a pre-determined solid color (such as a particular shade of blue or green) with another video image. A common example of chroma-keying is a television weather report. In the studio, the weather reporter is merely pointing at a blue screen. In the control room, the blue is replaced with an image of the map, satellite images, or Doppler radar. Chroma-keying is not foolproof, and often if the weather announcer is wearing clothing possessing the same blue shade, the weather map appears on his body. Also spelled as two words, chroma keying.