If you’ve taken up watercolors, you’re surely familiar with the popular colors of today: the Cadmium Reds and Yellows; Hooker Green, Sap Green, and Viridian; Cobalt, Cerulean, Prussian Blue, and Ultramarine. There are a few colors you don’t hear much about anymore. Why don’t people use them? Green Bice (above) Also called Verditer…