The apparatus comprises of what appears to be a regular artist pallette, with four blobs of paint in different colors. Just wave the pallette, and the colors vanish, leaving four black (empty) spots in their place. You can also do this in reverse, having the four colors appear in place of the empty spots. This goes very well with coloring props like The Magic Coloring Book, Color It, Amazing Birthday Bear picture frame etc.
After showing the black and white picture(s), display the pallette with the colored spots, wave it over the picture(s), and show the colors have vanished. Then show the picture(s) is colored. It can be used to transform four white ribbons or silks to four different colored ones (in a Change Bag).
The different colored silks or ribbons could then be used for a follow up effect. There are also effects with silks like the Happy Birthday Dyeing Set, A Merry Xmas Dyeing Set, where the pallette can be incorporated for an additional touch of magic. It can be used in silk dyeing effects (via a dye tube). You can use it with a Genii Tube, where you pour water into the tube and pour out different colored liquids, and silks to match the liquid. Use the pallette to transfer the colors. Wave it before a handkerchief (or a pair of handkerchiefs) for your Coloring Changing Silks.
There are Colouring Changing Penknives, Wands, Rope, Neck Ties, and even complete dresses amongst magicians props. And the imaginative performer can incorporate the pallette with many of these effects for that added magic touch.