Long-exposure photography or time-exposure photography or slow shutter photography involves using a long-duration shutter speed to sharply capture the stationary elements of images while blurring, smearing, or obscuring the moving elements. Long-exposure photography captures one element that conventional photography does not: time. The paths of bright moving objects become clearly visible. Clouds form broad bands, head and tail lights of cars become bright streaks, stars form trails in the sky and water smooths over. Only bright objects will form visible trails, however, dark objects usually disappear. Boats during daytime long exposures will disappear, but will form bright trails from their lights at night.