Shadows and Silhouettes
Shadows can add a lot to a photograph. They can emphasize emotions, create surreal images, and be used in a variety of ways. While strong use of shadows in color photographs tends to be mostly used in silhouettes, it can also appear in a variety of other forms in color photos as well. In my opinion though, shadows are most powerful when used in black and white photographs.
How to Shoot a Silhouette
Take your exposure from the brightest part of the image – that should be the background – and turn off any automatic flash that could illuminate the subject from the front.
Make sure that the frame remains clutter free. If there is too much going on you will end up with a huge black blob that makes no sense to anyone, success will depend on knowing what the main focus of the image is.
People are an obvious choice to be silhouetted, especially in action. The black outlines of a person are instantly recognizable and can be a powerful portrait image. I have shot quite a few silhouettes on beaches; in most cases the big open space is perfect for framing your subject.
when you edit your shadow selects you will need to increase contrast and might need to increase the highlights. You will also need to crop to just show the shadow. Nothing else in the shot matters but the shadow; after all it is your subject matter.