This chart shows Terra Rosa mixed 50/50 with each color going across then tinted with white going down. Terra Rosa is a wonderful color for landscape paintings. Again, had I mixed a little more white each time, I would have gotten all the way to white at the bottom.
I don't look at these charts all the time. But, sometimes I'm standing at the easel, looking at the set-up, or a shadow, and I just don't know what colors to mix. These really help. I've also done many of these color value scales just mixing colors, not adding white.