Most stage productions rely on Parabolic Aluminum Reflector lamps (par cans), which provide good light and can be moved very easily. Scoop lights act as flood lights, allowing the entire stage to be lit with comparatively few lights, while followspots can spotlight and follow a particular actor around the stage. Fresnel lights are set up on tracks and usually serve to accent the stage with color. Ellipsoidal lights provide multiple effects, i.e., the ability to shift between sharp and soft focus thanks to the use of a movable lens tube. Along with par cans, ellipsoidal lights constitute a staple of stage lighting equipment.
Placement and direction of the lights goes a long way towards establishing a particular mood. Obviously, the lights need to reveal the performers and/or scenery, but the time and direction of the reveal can convey a specific effect. Lighting on the front of the stage serves mainly to provide visibility; when only one light is used, it creates a very flat effect, although "fill" lights placed at angles from the "key" light can create a natural look with a solid sense of depth. Back lighting from the rear of the stage accentuates the edges of any objects, highlighting the performer's hair and outline; it is often used for effect. Side lighting from either side of the stage draws attention to movement and accentuates the colors of other lights. Foot lighting from below the performers creates a weird, eerie effect suitable for mystery stories and works of horror.
Gels are pieces of colored plastic that can be slid over lights to bathe the stage in particular hues. The exact shade and intensity of the hues creates specific effects. Red creates a mood of passion or excitement, while yellow creates a more cheerful mood. Blue conveys calm or muted emotions, while pink is upbeat and peppy. Green conveys a sense of strangeness, and lavender produces a soothing atmosphere conducive to relaxation. All of them can be adjusted and varied to adjust the overall tone of the play.