Oil on paper, 9" x 12"
I've been creating colour mixing charts in oil (as per Monsieur Schmid, even though I don't own his wonderful-looking book); it is feeding my methodical side (nerdy? OCD? :D :D :D). Seriously though, I do these every few years to remind myself how many mixes can be obtained from just a few key colours. This time, I used my bargain pack of RT Rembrandt primaries plus white.
The mixes on the top row are pure Permanent Yellow Light, Permanent Yellow Light with a touch of Permanent Red Medium, PYL with a touch of Ultramarine Blue and PYL with a touch of both PRM and UB; on each chart that particular 'primary' is dominant in each of the mixes. Going down each column, I've used increasing amounts of white to create tints.
I used a tiny palette (painting) knife to mix and apply the paint swatches. The number of possible variations never ceases to amaze me. (I will also post the red and blue palettes.)