What concept involves controlling the light using dimmers and colored gels?

The concept that involves controlling the light using dimmers and colored gels is intensity. Intensity in lighting refers to the brightness or power of the light being emitted. Dimmers are devices that allow for the adjustment of light levels, enhancing or reducing the intensity of the illumination in a performance space. This capability is essential for creating different moods and atmospheres, as varying intensities can evoke different emotional responses from the audience.

Colored gels, on the other hand, modify the color of the light while also influencing its perceived intensity. By layering different colors and adjusting the dimmers, lighting designers can achieve the desired artistic effects that complement the overall production design. This understanding of intensity is crucial for guiding the audience's emotional experience, underscoring dramatic moments, or highlighting specific actions on stage.

While other concepts such as direction, texture, and distribution play significant roles in the overall lighting design, they do not specifically focus on the manipulation of brightness or color to create mood and atmosphere in the same way intensity does.