What type of lighting cue involves both intensifying and dimming lights?

The choice of fade up/down is correct because it specifically encompasses the process of gradually increasing (intensifying) or decreasing (dimming) the brightness of the lights in a performance. This technique is essential in creating transitions in mood, atmosphere, or time, allowing for a smooth visual flow that supports the narrative.

In contrast, the other options represent distinct lighting techniques that do not combine both intensification and dimming within the same cue. Crossfades typically involve overlapping two light sources, creating a seamless transition from one to the other without emphasizing both actions of increasing and decreasing the same light. Follow spots and profile spots refer to specific types of lighting instruments with unique functions—follow spots track performers, while profile spots are designed to create sharp-edged beams—rather than focusing on the gradual light adjustments central to the fade up or down technique.