Here’s another type of artistic expression unique to photography, the multiple exposure. Originally, in film, the photographer would typically turn a switch on the camera to stop the film from advancing and then re-expose the frame. Today this is easier to accomplish and much easier to explore with digital slr cameras. My Nikons have this feature built in, with settings allowing me to choose how many images and even doing some of the exposure work for me. The image on the left is a piece of yard sculpture in my sisters yard. By taking multiple exposures, while hand holding the camera, it created a layered affect with the rusty metal turning into shades of pink and the leaves and grass blurring to becme a background.
Freeman Patterson, a great Canadian Photographer wrote a great book on such techniques, Photo Impressionism AND THE Subjective Image, which I highly recommend, as well as all his books. You’ll find more at http://www.freemanpatterson.com