Good questions! You might also ask why I used infrared. The stone mills are strange and beautiful places to me, with beautiful light. I think of them as primative temples, filled with objects symbolizing ancient mythology, primative human emotions and spirit. These huge wheels embody power and mystery which I try to capture in my work. The etherial light and texture is accentuated in infra red. Much more effective in the original 11x14 silver enlargement. I have a series on the stone mills on my web gallery.