三级色是中性的棕色与灰色，在调色板中使用的时候，经常被代指为泥巴色。因此经常会被从调色板中排除掉，不过它们也很重要。三级色能够让明亮色调更突出，在表达细腻的想法或者是氛围的时候很重要。

Tertiary colors are the neutral browns and grays that, when over used in a palette, are often referred to as "mud." Though sometimes banished from an artist's palette, they play a crucial role. Tertiary colors give more vibrant hues a chance to shine and play a starring role in compositions with more subtle ideas or moods behind them. Follow along with Mary Jane Begin in this installment of Artist at Work as she explores tertiary color, its best uses, and the creative possibilities available with this palette. She paints a landscape based on a reference photo, and provides tips along the way about establishing a ground, adding texture physically or digitally, building depth, and making your focal points pop.