A beam of light is invisible in clean air — you only see where it lands. To see the beam itself (the aerial looks that make concert lighting), you need particles in the air for the light to scatter off. That is what haze and fog do.
Haze vs. fog vs. low fog
- Haze — a fine, even, long-hanging suspension. The workhorse for revealing beams without looking "foggy". Water- or oil-based.
- Fog — denser, thicker bursts; great for reveals, but dissipates faster and can obscure.
- Low fog — chilled fog that hugs the floor for the "walking on clouds" look.
The practical catch
Atmosphere is a balancing act. Too little and beams vanish; too much and you trip smoke detectors, fog up the room and choke sightlines. Hazers need warm-up time and the HVAC will move the haze around — plan for airflow, and always clear it with the venue and fire safety first.
Tip: a little haze plus strong back and side light reads as far more atmospheric than a lot of haze with flat front light. The angle does the work.