RGB Color Model
In the RGB color space a color is defined by their shares of red (R), green (G) and blue (B). It is an additive color model, in which the colors are achieved by mixing the respective shares. This color space is used for systems with emitting light, such as monitors.
Depending on the purpose, the shares are notified in percentage (0 to 1 or 0% to 100%), absolute values (0 to 255) or hexadecimal (00 to FF). The hexadecimal notation in the form #rrggbb is primarily known through HTML and CSS.
If all shares are zero (#000000) the color is black, if all shares are maximum (#FFFFFF), the color is white. In between these two values, there are all the other colors. Gray (see table with gray) from white to black would arise if all of the three colors are available in an equal share (for example #131313 or #444444), a pure red arises, for example, only by a red portion (# FF0000), a pure yellow by the mixture of red and green (#FFFF00).
The program pipette provides the hexadecimal notation and the percentage and absolute values automatically. For the hexadecimal notation see "HEX" in the first row, the absolute values you can find in the row "RGB" and the percentages in the line "RGB%".