An artist may have one of these boards with a thumbhole on which to mix his paints
The kidney-shaped variety has a thumb-hole at one end and is... [DOC] [TLE] Muddy Colors: Tips and Tricks and your suggestions #2 - Palettes [PAR] Apr 18, 2011 ... One problem I do have is keeping my paint (acrylic) wet and ... art supply paint 
boxes and my haloed drawing table's surface to mix paint .... Oils... the glass 
palette of my own making so I can make it any size.