Tkinter 8.5 reference: a GUI for Python

To give your application's user a popup they can use to select a color, import the tkColorChooser module and call this function:

result = tkColorChooser.askcolor(color, option=value, ...)

Arguments are:

If the user clicks the OK button on the pop-up, the returned value will be a tuple (triple, color), where triple is a tuple (R, G, B) containing red, green, and blue values in the range [0,255] respectively, and color is the selected color as a regular Tkinter color object.

If the users clicks Cancel, this function will return (None, None).

Here's what the popup looks like on the author's system: