Here is my latest contribution to color blend experiments.
Sometimes you will need a blend with a lot of contrast. Sometimes you will want a very small change in color. For the most contrast in a color blend, use even amounts of each color. The line across with be at a 45 degree angle from the sides.
The dark in this blend was made with Premo colors. 1 part alizarin and 1 part ultramarine blue.
To make a dark blend with less contrast use less white. The angle of the line between the colors determines the contrast. If the line were straight across, there would be no contrast. It would just be a solid-color mix. Now the line is slightly more horizontal and therefor there will be less contrast.
To make a lighter blend with less contrast, use the same angle but use more white.