An overview of techniques and equipment to make light do more than just illuminate. It’s possible to achieve a range of effects easily and reliably without resorting to more complex digital techniques. Although of course if you already have projection equipment and operators available, it’s sometimes easier to do some effects digitally.
Projected Effects – Optical Effects Disc (1925 – present)
Although expensive to hire, a moving effect disc and an effects projector can add a layer of polish to a production. The principle is simple – the effects projector lantern is fitted with a remotely controllable glass disk which has been painted with various effects (e.g. clouds). In front of this a lens is fitted to focus the image.
An adjustable masking plate can be added to reduce the image size to avoid unwanted spill.
A variety of lenses is available to produce the correct image size and throw distance.
Available disks (VSFX3 system from City Theatrical):
- Fleecy cloud
- Storm cloud
- Thunder Cloud
- Fire (Flames)
- Running Water
- Vapor Trail
The first effects discs used a clockwork motor, which was activated by pulling a cord attached to the front of the unit. The modern device uses an electric motor which requires a non-dimmed power supply. There are two types of electric disks – the more modern ones have a DMX512 control interface. Using this, the lighting desk can control the speed and direction of rotation. The only adjustment required to the disc is to set the DMX address (the channel number on the lighting desk to which the disc will respond).
The older type of disc has selectable speed and direction on the motor housing – this is obviously not adjustable during the performance.
- Be sure to always have the disc turning BEFORE turning on the lamp – this will prevent expensive damage to the painted surface of the disc. Hire companies will place warnings of financial penalties if this instruction is ignored. The discs are costly to replace and once damaged, can’t easily be repainted as it will be visible once the image is blown up.
- On older equipment, the electric motor can be quite loud at fast rotation speeds. Slow the disc down for a quieter life.
- The projector must be rigged within a few degrees of horizontal. This ensures the disc can spin freely. A beam diverter mirror can be used to project the image down onto the stage.
- The objective lens on the front of the projector must be securely fastened in place using either a elasticated strap or fixing bolt.
- Great care must be exercised when rigging the projector – the weight is considerable. The effects projector lantern itself should be rigged in position first, then the disc, lens, and any other accessories should be added.
Gobo (Pronounced “GO-bow”, not “gobbo”, with “bow” as in bow and arrow, not “take a bow”. Who said English was easy.) A gobo is a round metal or glass disc with an image or shape etched in it which can be projected by inserting the gobo into a profile lantern.
A gobo holder must be used to hold the gobo in the correct position. The gobo holder is inserted into the “gate” of the profile, which is usually half way down the lantern.
Gobos are most effective when the light levels are low enough to enable them to have a strong effect on the lighting state. The texturing of the light can evoke a particular location (e.g. dappled light through trees, or light through a large window) or emotion (the isolation of a set of prison bars, or a slash gobo for tension or conflict).
In addition to the metal designs commonly available, there are an increasing range of glass gobos, which have a higher level of detail (the glass Moon gobo shown below is photo-realistic). There are many different sizes of gobo and holder, and it’s important to ensure you’re using the correct gobo for your profile lantern.
Different sizes of gobos are available, and these must be matched to a gobo holder, which in turn must be matched to the profile lantern you’re planning to use.
If you don’t have gobo holders in stock for your particular lantern stock, they’re a good investment.
Used on the front of a profile lantern with a gobo, the animation disc can provide a sense of movement.
See Projected Effects above.
Reflected Light from Water – Tubular Wave Ripple
This effect uses a linear lamp mounted behind a rotating metal tube with cut out slots. It works best when positioned on the floor just in front of a backcloth or piece of set, and gives the appearance of light reflected from waves lapping against the side of a pool or ship.
See Projected Effects above.
A variety of different effects are available, many using LED light sources for long life and reliability.
Below is a video showcasing the Chauvet Abyss effect.
Historical information on the Up/Down Sea Wave Effect coming soon.
1) See Optical Effects Projector above.
2) Silk Flame effects, consisting of a fan, a small piece of silk, and a light source, can be used for handheld flaming torches – they’re remarkably effective and very safe. The West End and Broadway productions of Wicked and Young Frankenstein use silk flames.
3) A ‘Faux Fire’ effect can be used with great effect. A light source and a mist generator in combination can produce a highly effective end result.
Below is a demonstration of the Technifex Faux Fire effect that’s used in theme parks.
4) Flicker Flame effect
This beautifully simple effect uses a motorised disc with randomly cut out shapes which spins in front of a piece of pebbled glass. When the effect is mounted on a small lantern (500-650W PC is ideal) the effect of light from a fire is cast on the stage. The motor needs a separate power supply, and should not be plugged directly into a dimmer.
The lantern plus the effect is small enough to be mounted in a stage fireplace, and with low lighting levels looks magical. Although the unit is designed to replicate fire, by replacing the orange gel supplied with a blue, an “underwater” effect is produced.
Some hire companies have been inexplicably getting rid of these effects in the past – if you get a chance to buy one you won’t be disappointed.