Example 1: Angle of Light Source, Mesquite Flat Dunes in Death Valley

Mesquite Flat Dunes This image was taken within an hour of sunrise, when the sun was no more than about 10 degrees above the horizon. The effect of the low angle is seen in the visible shadows on the individual sand grains, which gives the surfaces a granular texture. Over the second hour of sunlight, the incident angle of light became too high to project a visible shadow on the sand grains, resulting in a loss of texture. Eventually, the sun angle progressively eliminated the shadows on the smaller, and then larger sand ripples.