Flicker Generator

Overview

A Flicker Generator (also Flicker Box or Flicker Dimmer) is an electronic control device in film lighting that rapidly and precisely modulates the brightness of connected light sources. This creates flickering light effects that simulate natural or technical light sources in the image – such as the blaze of a fireplace, the flicker of a candle, the changing glow of a television or film projector, a welding arc, a faulty fluorescent tube, or lightning from a thunderstorm.

Classic devices switch dimmable incandescent light sources (tungsten); modern generators control LED lights, fluorescent tubes, or dimmer packs – often via DMX protocol. Multi-channel devices allow multiple lights to be controlled independently from different angles, creating moving, wandering shadows for fire effects.

Functionality

The generator outputs pre-programmed or controllable flicker curves that describe the temporal brightness progression of an effect. For fire, multiple channels work intentionally against each other (interactively random) so that the light does not pulsate synchronously but fluctuates irregularly like a real flame. Intensity and speed (rate) of the effect can typically be adjusted via controls.

• Single-channel: simple flicker on one light – suitable for a candle, TV glow, or a single fire glow.
• Multi-channel (usually 3 channels): separate control of multiple lights for moving shadows, RGB television effects, or complex fire simulations.

Devices and Technical Data

Common professional devices include the LFX Master (LFX Tools / movie-intercom, Berlin) and the Magic Gadgets Shadowmaker series. They differ fundamentally in the type of light control: DMX-based devices control fixtures digitally, while classic dimmer boxes switch the mains directly.

On-Set Usage

The Flicker Generator is connected between the control source and the light fixture: for DMX devices as an inline unit in the DMX line, for classic boxes directly in the power path between the dimmer/mains and the lamp. Typical applications include casting fireplace or campfire glow onto actors, the changing TV glow in a dark living room, simulated welding light, or flickering lightning effects. For believable fire shadows, multiple lights are operated from different directions on separate channels. For loop-based effects, attention must be paid to synchronization with the camera frame rate to avoid visible moiré patterns.