Open loop and closed loop lighting patterns are two lighting techniques used in photography, especially in portrait photography, to create different effects on the face of the subject.
The open loop lighting pattern is created by positioning the key light source, which is usually a studio light, to one side of the subject's face and slightly above eye level. This lighting pattern creates a shadow on the opposite side of the subject's face, with a small triangle of light visible under the eye. This is also known as the "Rembrandt lighting" pattern.
On the other hand, the closed loop lighting pattern is created by positioning the key light source directly in front of the subject's face, often from above. This creates a soft, even illumination on the face, with no visible shadows.
Both lighting patterns can be implemented on faces, and the choice between the two will depend on the desired effect. The open loop lighting pattern creates a more dramatic effect, adding depth and dimension to the subject's face. This pattern is often used to highlight strong features, such as cheekbones, and is ideal for creating a moody, dramatic portrait. In contrast, the closed loop lighting pattern creates a more evenly lit face with a softer, more flattering effect. This lighting pattern is ideal for portrait photography that aims to create a gentle, serene or approachable appearance.
It is important to note that open loop lighting may not be suitable for every face shape or every situation. This lighting pattern can be particularly harsh and unflattering on subjects with prominent or irregular facial features, and it can create unappealing shadows in certain situations. Additionally, the open loop lighting pattern may not be appropriate for some types of photography, such as product photography, where a softer, more even lighting is needed.
In contrast, the closed loop lighting pattern may not be suitable for situations where you want to highlight specific features or create a sense of depth and dimension in the subject's face. This lighting pattern may also create a flat, uninteresting portrait if not used correctly.
In conclusion, the choice between the open loop and closed loop lighting patterns will depend on the desired effect and the subject's face shape and features. When using these lighting patterns, it's essential to understand how they work, experiment with them, and evaluate the results to determine which lighting pattern best suits your subject and situation.