What is the RGB color space?

Because the human eye only has color sensitive receptors for red, green and blue, it is theoretically possible to decompose every visible color into combinations of these three “primary colors.” Color monitors, for instance, can display millions of colors simply by mixing different intensities of red, green and blue. It is most common to place the range of intensity for each color on a scale from 0 to 255 (one byte). The range of intensity is also known as the “color depth”.

The possibilities for mixing the three primary colors together can be represented as a three dimensional coordinate plane with the values for R (red), G (green) and B (blue) on each axis. This coordinate plane yields a cube called the RGB color space:

If all three color channels have a value of zero, it means that no light is emitted and the resulting color is black (on a monitor, for example, it cannot be blacker than the surface of the monitor producing 0 light). If all three color channels are set to their maximum values (255 at a one byte color depth), the resulting color is white. This type of color mixing is also called “additive color mixing”:

If you draw a diagonal from the black (0, 0, 0) origin point of the color cube to the white (255, 255, 255) point, you will get a line where each point on the line has identical R,G and B values. The result of having the same value for all three color channels is the color gray. The only thing that changes as you move along this diagonal is the intensity of the shade of gray as you go from black to white.

Best regards,

Frank Karstens

The Basler Support Team