This photo shows the current stage of the painting. The photo was taken outside this evening and has some glare and a blue cast, especially on the viewer's right. There really is purple, orange, and red along with the blues and greens. I will continue to work on the values and the shapes of the cows and the mid-ground planes, before adding a more distant cow or two and completing the tree behind the foreground cow.
One way I check the values is by converting the color photo to grayscale. The other way is by squinting my eyes until I see only the mass tones. As can be seen, the cow is very dark because the light is coming from behind.