When you look at photos you’ve captured during a visit to a national park unit, do you notice one or more of your shots clearly showing a division of light and dark, or energy and calm, or two different colors, or two different textures? Contributing photographer Rebecca Latson sees this phenomenon in many of her own images, calling it the “yin and yang of a composition.” In this month's column, Rebecca provides examples of this yin-yang concept and how you can look for it in nature with your camera.