Atmospherics
While not a 'lighting effect' per se, the use of atmospherics (any particulate put into the atmosphere) winds up having a large effect on the lighting environment for the production, so it is often an element that falls under the lighting designer's purview.
There are three general types of atmospherics: Haze, Fog, and Dry Ice or Low Lying Fog. Some quick definitions of each:
There are three general types of atmospherics: Haze, Fog, and Dry Ice or Low Lying Fog. Some quick definitions of each:
- Haze is an atmospheric that hangs somewhat evenly in the air. To describe it, I often will suggest that it is like a 'foggy morning'. There is a certain 'thickness' to the air, and while it does not billow like smoke, the viewer is definitely more visually aware of the air itself. Haze essentially disperses tiny particles into the air which reflect light. When haze is used correctly (i.e. distributed evenly throughout the space), its presence should be mostly imperceptible except when light is shone through it. This is the way that the audience can see the beam of the light.
- Fog is what a fireman would call 'smoke'. The atmospheric does billow, and the viewer can see clouds and wisps of the fog in the air. Fog has a much more specific presence in the stage environment than does haze. Fog is used when a prop smokestack needs to billow smoke, or when showing that steam is coming from a street grate.
- Dry Ice is the generic term for any fog that is heavier than air so that it hangs along the floor of the space. This is the type of fog that you might see in monster movies or graveyard scenes.
HazeLighting designers will specify haze when it is important to see the beams of the light in the design. This way the cone of light, or the pattern of light between the lighting instrument and the stage can become a shape element. This is a very common element in presentational work such as rock concerts, but also has use in theatre.
When the edge of the light is focused sharply, the edges of the beam (whether or not a gobo is used) will be very distinct in the air. On the other hand, if the edge of the beam is soft (whether it is an ERS focused softly, or a naturally soft beamed instrument such as a PAR or Fresnel) the effect in the air will be much more general, showing color and direction more than shape. |
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using haze
The key to the effective use of haze is based on two variables: Placement and Volume. Because the intention is usually to fill the room with atmospheric without the 'source' being perceptible, hazers are usually placed far offstage, so that by the time the haze gets to the part of the stage visible to the audience, the 'cloud' and movement of the material is mostly imperceptible. Volume is essentially 'how much' haze is in the air. The machines can be manually adjusted, or controlled by the lighting console so that the perfect amount of haze stays in the air. Too little volume, and there will not be enough particulate in the air for the light beams to be visible. Too much, and the air begins to be 'too cloudy', and begins to distract from the action of the play.
Fog
Fog is often used more as a light-able scenic element than is haze. The billowing smoke has a shape of its own, and does not rely on lighting to define its shape. The direction and source of the smoke is often a significant element in its usage. Volume (how much fog there is) is of course a significant element here as well as haze, but another variable placed into the equation when using fog is that of Dissipation, or how quickly the fog disappears into the air. The fog machine uses different types of fluid, from Regular (longest lasting) to Quick-Dissipating which disappears a little faster, to Very-Quick Dissipating which disappears even faster than that. Some machines can also produce colored fog, again based on the fluid chosen.
Dry ice fog
Dry Ice is solid Carbon Dioxide, which has the unique property of transferring directly from solid to gas as it warms (sublimation). This gas is a visible smoke which is heavier than air. This effect has been used in theatre for many years, but because elevated Carbon Dioxide levels can be dangerous or fatal (CO2 displaces oxygen and can cause suffocation), manufacturers have come up with other ways to create low lying fogs through the use of fog machines and chillers (without using actual Dry Ice).
A few more things about atmospherics
There are several companies that produce atmospheric devices. Each of the manufacturers have a multitude of promotional material and video on their websites. Some of these are: Le Maitre, Rosco, Chauvet, Martin and American DJ. When choosing a machine to create the atmospherics for a production it is very important to research the different types of machines that are available, because the range is vast. American DJ is a company that focuses mostly on very small venues (like wedding reception ballrooms), so as a result these machines may not have enough punch to be effective in a medium to large theatre space. On the other end of the spectrum are devices designed for arena rock shows, which need to fill a much greater volume of space. These machines, even set on the lowest volume setting would quickly overwhelm most theatre auditoriums, and would be equally as inappropriate. The costs of the machines is also in a wide range, from $30-40 to thousands. Remember that 'you get what you pay for'.
Another important thing to remember is that atmospheric fluids are specially engineered to work with the machines from the same manufacturer. Fog fluids are not interchangeable! If you have a Rosco machine, you must use Rosco fluid. This is not just a money-grab: the engineering involved is very specific, and if the wrong fluid is used it will either not work, or will possible ruin the machine!
Another important thing to remember is that atmospheric fluids are specially engineered to work with the machines from the same manufacturer. Fog fluids are not interchangeable! If you have a Rosco machine, you must use Rosco fluid. This is not just a money-grab: the engineering involved is very specific, and if the wrong fluid is used it will either not work, or will possible ruin the machine!