While mixing sample colors to match her Blue Ombré rendering, my student discovered the perfect ratio was 1 part Ultra Marine Blue with 1/4 part orange to knock out the purple and dull it down a bit. Still very blue, but not as warm.
Today we took that ratio full scale and I swear to god it went a deep purple blue. She tried more orange and no luck. We poured off small bits to try new colors mixed in to knock that purple back, and get back to our blue. We tried a Golden yellow, A raw umber, a burnt umber, a cerulean just for kicks, along with a burnt Sienna and a yellow ochre.
The winner. Pthalo Green.
So now we are going to have a lot of blue purple marble in painting class as we have close to a gallon of the wrong color that needs a home.