Video monitors display video images from cameras and recorders, often using cathode ray tube (CRT) technology. Industrial units typically have higher resolution that consumer monitors or televisions and can have additional functions such as zooming and multiple signal display. Video monitors can operate in black and white or color.  Black and white is monochrome, or grayscale; the image is presented in black, white, and grayscale.  The range of colors is generated with varying combinations of different discrete colors.  One common technique is sensing the red, green, and blue components (RGB) and combining them to create a wide spectrum of colors.