My daughter, Mary, and I came upon this herd of bison near the eastern trailhead of the Mary Mountain Trail.  The trail runs east to west across the central plateau of Yellowstone, a major bison migration route.  Mary Mountain (and Mary Lake) was named in 1873 by a tourist party, in honor of a young lady member, Miss Mary Clark.  This photograph was taken around 6 PM, looking south towards Hayden Valley.  The sunlight was striking the scene from the right. 

My primary objective for this painting was to capture the feeling of buffalo roaming the Yellowstone alpine tundra. I was particulary pleased with how the light affected the scene.  It enhanced the overall painting composition significantly.  Most notably, the large buffalo bull in the middle-right foreground was optimally illuminated.  Roughly two-thirds of his shape was sunlit, creating good variety.  Further, the lighting on his back overlapped the dark middle-ground.  And lastly, the bull's head, commonly dark in value, was in shadow, heightening it's dark value relative to other shapes in the composition.  The large clouds in the sky were creating sweeping shadows across the rolling landscape.  This shadow enhanced the separation between the foreground and middle-ground, and created a great backdrop for the sunlit buffalo.