Colour Wheel:

D etermining colour codes Instructions:Hover over the colour wheel to choose the colour Hover over the square to change saturation (left to right) and value (bottom to top) .Use the keyboard :
j rotates slowly counterclockwise,
k rotates quickly clockwise, and
l rotates slowly clockwise. Jump to  colors: red, green, blue, cyan, magenta, or yellow. The enter key adds the current color to the pick list.