This is not a stand alone magic effect, but a prop you can use in conjunction with many other colouring effects to enhance the routine. The apparatus comprises of what appears to be a regular artist pallette, with four blobs of paint in different colours. Just wave the pallette, and the colours vanish, leaving four white (empty?) spots in their place. You can also do this in reverse, having the four colours appear in place of the empty spots. This goes very well with colouring props like The Magic Colouring Book.