When working with design graphics or creating artistic works on the PC, it is essential to have a colour selector and generator like this one: RGB Selector. This simple program uses three sliding bars that let you represent any colour, also generating its RBG or hexadecimal code.
As with any decent selector, you can also indicate any pixel on-screen and the program will tell you its code to use it in other places (the "Capture pixel" option). Another possibility is to randomly generate colours (the "Rand colour" option).