When an object casts a shadow, the side away from the light will also be in shadow. These form shadows are softer, often less defined than cast shadows. When taking a person or other object out of its original photograph to place in a layout, pay attention to the shadows and lighting on the figure. If the cast shadow you apply is inconsisent with the existing shadowing on the figure, you may need to apply brightness controls to select portions of the figure to recreate form shadows that match your new imaginary light source.