RGB color uses the additive colors: red , green, and blue.
Additive colors are produced by light sources, not by reflection from the surfaces of objects, as are the subtractive colors.
Because additive colors are produced by light sources, they're often called lights.
The brightness (luminosity), of the red, green, and blue lights, is designated by the numbers from 0 through 255.
When the red, green, and blue lights are at their brightest, 255, white light is seen.
When all of the RGB lights are off, 0, no light is seen.
When all of the RGB lights are on, and their brightness (luminosity) is the same, various shades of gray are seen.
When one of the lights is on, and the other two lights are off, the color (hue) of the on light is seen.
The above colors, red, green, and blue, are the primary color lights.
Colors other than the primary color lights are produced by varying the numbers.
128 green was added, reducing magenta, making an orange light.
Just as the brightness of gray was varied by changing the numbers, the brightness of a color is changed by:
• Varying the color's number.
• Keeping the other colors the same.
Below, the brightness of the red primary light is changed.
The saturation of a color can be changed by increasing or decreasing, equally, the other two colors.
When the RGB values are far apart from each other, the color is more saturated.
As the RGB values become closer to each other, the saturation is decreased, because gray is being added.
The RGB values are far apart, so the saturation is high.
90 green & 90 blue were added, reducing the saturation of the 255 0 0 red.
The RGB values are closer together, reducing the saturation.
180 green & 180 blue were added, further reducing the saturation.
The RGB values are even closer, reducing the saturation greatly.
Hexadecimal color is another away to define color.
Go to Hexadecimal Color.