The Triadic scheme uses colors that are 60° apart on the color wheel. Because red is a primary color, the two colors 60° apart are also primary colors - blue and yellow. If we had started with a secondary color such as orange, it's triadic scheme would use green and violet (secondary colors). This "primary, triadic" color scheme is the one often used to color children's toys. The paler shades are often found in nurseries and the brighter shades in toys for older children. I personally find it to be the most difficult to work with because it has no "common ground" (mixed colors) to pull the color together.
Notice also that as we mix the red shades with yellow and blue, we get our greens and purples. Also, the darker yellows resemble green. That is because to darken yellow it is mixed with black, which contains a great deal of blue. To avoid this, many painters will mix yellow with dark browns, achieving more ochre tones.
These are examples of Red's Triadic color scheme.
Triadic for Red:
Blue and Yellow
