You will need the three primary paint colors: red, yellow, and blue. Set the black and white paint aside for now. To use the color mixing board, pour out equal amounts of red, yellow, and blue ...

As we all learned in kindergarten, blue paint and yellow paint makes green paint. Try doing that in Photoshop, and you’ll get something altogether different—a vague, uninspiring brownish-grey.

The effectiveness of white lies in its undertones, which can range from warm — think soft and cozy with a gentle yellow beneath it — to cold white, which typically hues blue. And of course ...

I remember her crouching, when I was a child, before an open gallon of white, stirring in bluish gray from the moldings paint can. The added blue pigment, she explained, would counteract yellowing ...