The chrominance or color denotes a signal with information about the type of color in video technology. It is parallel with the luminance ( brightness signal corresponds, for reasons of compatibility often the pure black and white image) transfer. Both together deliver as part of a brightness - color model the complete information about the colored image.
In contrast, there are color models that specify a color locus by three basic colors, such as the RGB color space.
As perceived by human physiology due to its color space may be stretched in an area transmission or storage of a complete color information for the human observer having at least two independent chrominance signals must be made. In the adjacent diagram, this color space is shown as an example for the YUV color model.
The commitment to only two chrominance signals for the complete mapping of the color information, however, is not always given, but determined by the particular structure of the human eye. For organisms with a different color perception, such as marsupials or honey bees, would require an additional chrominance signals are added. This then results in higher-dimensional color spaces. On the other hand, would a TV for dogs and most other higher mammals with a single chrominance signal.
The two color signals required for human observers play a role in both the analog and the digital color television, in video transmission, color photography and the color models used in this case. In all these cases, Y is the brightness signal, the following two uppercase CbCr as the chrominance signals. These are formed differently depending on the application, resulting in the different designations: