RGB (or true colour) images are 3-D arrays that we may consider conceptually as three distinct 2-D planes, one corresponding to each of the three red (R), green (G) and blue (B) colour channels. RGB is the most common colour space used for digital image representation as it conveniently corresponds to the three primary colours which are mixed for display on a monitor or similar device.
We can easily separate and view the red, green and blue components of a true-colour image. It is important to note that the colours typically present in a real image are nearly always a blend of colour components from all three channels. A common misconception is that, for example, items that are perceived as blue will only appear in the blue channel and so forth. Whilst items perceived as blue will certainly appear brightest in the blue channel (i.e. they will contain more blue light than the other colours) they will also have milder components of red and green. Following image will show color space as cube :
White color is generated when all (RED, GREEN, BLUE) colors are mixed. Shown above.