Learn by doing: mix two gouache primary colors

Which colors should you use for your primary paints? See how different these gouache mixtures appear when I use different paint colors to mix for my primary colors. 
  
I used Bristol board, Artist Loft paints, and a 10 broad flat brush. For each sample, I began with the lighter color on the left, added the color on the right end and expected to end with it. 

Paint Mixing Explorations

With a dab of the lighter color, I added a teeny-tiny paint amount of the color at the farthest right end. I blended the paints then stroked the Bristol board with the mixed color. Then I added another small amount of the farthest right color to my previous mix. I repeated this until I reached the color on the right, my darker color. I gradually mixed the paints and stroked them across the paper’s space. 

Exploring your paints this way develops your mixology skills so you make the color combination you want every time. It also helps you learn in case your paint collection misses a tube color you want.