Great Falls--01526

This is one of my favorite moonlight photographs. The different shades in the water are caused by the differing albedo (reflectivity) of the Potomac River where it falls, flows smoothly, tumbles over rocks, and swirls in eddies from the strong current below the falls. The bluish-green color of the calmer water is primarily a reflection of the color of the night sky, but may have some small aspect of reciprocity failure evident also. This image took about 11 minutes to fully expose.