The current color selected in the Color panel is displayed on a large corner square. Left-clicking on the square opens the standard Select Color dialog box. Right-clicking on the square opens a menu of available color modes: Grayscale, RGB, Lab, and CMYK.
By moving sliders or entering numerical values into the fields, one can change the individual color values of the selected color. At the bottom of the panel is a small spectral bar; bringing the cursor over this will cause it to take the form of an eyedropper. To choose a color, click with the eyedropper within the bar.
The empty squares at the top are used to store frequently used (custom) colors. To add a color to the box, drag it from the large color square. To change the main color to that in a box, left-click on a box. To remove the color from a box, right-click on it.
Select Color Dialog:
Most of the window is occupied by a square box, where you can choose a color and adjust its saturation. Using the vertical gradient stripe and the slider on the right side you can change the color brightness.
Three squares at the top display the last used colors.
Below, you can choose a color space (RGB, Lab, or HSL) and set the color if you know the exact values of its components.
Also, you can choose a color by entering its hexadecimal code in the Web Colors field. The six-digit code consists of three pairs: the first pair describes the amount of red, the second pair - the amount of green, and the third pair - the amount of blue. For example, "000000" is black and "ff0000" is red.
In the boxes located below, you can save the frequently used colors. Just drag the color from an upper large square. Press the Add to Custom Colors button to add the current color to a box.