That's a lot of bull, but what he said next was worse. "And never mix more than two colors together - or you'll get MUD!"
Many watercolorists have a morbid fear of making MUD, and it shows in the timidity of their paintings. They become obsessed with 'saving the white paper' and trying to protect the purity of their color, and they miss a lot of chances to make their paintings interesting and exciting.
In this class you'll learn to like - maybe even love - playing in the watercolor version of 'MUD' and you may be surprised at the way it affects your painting.