Nice explanation of RGB

And again.. as you are working with your images, how does this information become practical? Because you can measure the RGB values of a particular area and understand what those numbers imply. If the RGB values are the same (or close) you know it’s a neutral tone (black, grey, white). If the blue value is higher you know it has a more blue tone, green higher a more green tone, etc.

It also helps you gauge the brightness of that area. Anything that is supposed to be “white” should be at about 95% in each channel (RGB). That comes out to About 242 out of 255 for the brightness value (each pixel can have a value of 0-255).