How did Rembrandt use portrait lighting to create dramatic and expressive effects in his paintings?

Rembrandt used portrait lighting to create dramatic and expressive effects in his paintings by employing a technique called chiaroscuro. This involved using strong contrasts between light and shadow to emphasize certain features and evoke a sense of depth and emotion in the portrait. By strategically placing light sources and shadows, Rembrandt was able to enhance the mood and character of his subjects, making his portraits more dynamic and engaging.