A rich color is made with many colors. It is not so important which colors. A good place to look for rich colors is in the natural world. The yellow of a banana has blue, green, red and probably even some purple mixed in. There is also a lot of white to keep it light.

There is no need for a recipe to create great color. Color is all relative to what is around it in your painting. If you want to make something blue, instead of just using the blue straight from the tube (highly saturated), try adding some orange and a little bit of green and purple to the blue, then adjust the value with black-and-white and you will find that this blue will look richer and will relate more to the other colors in your painting. The wonderful thing about creating color is that it is entirely visual and you do not need a recipe.