Fill light

Fill light is used to illuminate shadow areas created by the key light, reducing contrast and revealing detail in darker areas. It is typically less intense than the key light (often 1-2 stops dimmer) to maintain some shadow for dimension. In product photography, fill can come from a second light source, a reflector bouncing the key light, or even a white surface. Proper fill is crucial for showing all product details without creating a flat, shadowless look.