Rob is a Lighting Designer and Lighting Programmer and currently Senior Lecturer in Technical Theatre Production. He is also the Editor of On Stage Lighting and teaches stage lighting practice.
The lighting control, “board” or “desk” is the a key part of any stage lighting set up and it is using the lighting desk that an operator is able to control the equipment. This can range from adjusting the “levels” on stage lighting dimmers to controlling complex intelligent lighting systems and media servers. Although there are many different types of lighting control, a great deal of the features are common to most and On Stage Lighting explains these features in the first part of beginner’s guide to the lighting desk.
Lighting Desk Output
How a lighting desk controls your rig depends on what kind signal it outputs to the various bits or equipment that it “talks” to. Some basic dimmers use different analogue voltages to interpret their channel “levels” and some top notch professional kit uses an ethernet network like a PC.
The standard in stage lighting control is the DMX512 protocol which means that that many lighting desks, big and small, output one or more DMX signals. There are very few things that you have to understand about DMX512 and using it in lighting control and they are detailed in DMX Lighting Systems – Is Anybody Listening?
Even the most basic lighting desk has a degree of channel control. This enables the operator to adjust the “level” (sometime expresses as a percentage – 0% – 100%) of a “control channel”. A lighting desk controls this channel which can be used to adjust a range of lighting equipment, traditionally the intensity of a stage light via a stage lighting dimmer. A modern lighting desk controls these “channels” using different input methods such as faders/sliders for intensity, numeric keypad (where you type in a value) and other weird wheels and dials. These wheels give the operator the ability to adjust parameters and levels, particularly in the control of intelligent lighting. Where lighting intensity is controlled by faders, an additional “flash button” is useful for quick flashes of each channel.
The master control faders on a stage lighting desk adjust the output channels levels on a global scale. The SubMasters can control different groups of lighting channels while the Grand Master adjusts the intensity of every channels as it leaves the lighting desk. It is worth remembering that, on a lighting desk with intelligent lighting control, the Master control faders only actually adjusts lighting intensity level channels.
Lighting Desk Playback
“Playback”, relating to a stage lighting desk, is a term used to describe the “playing back” of different scenes, looks or states during the show. At it’s simplest, playback is simply setting the channel faders on the desk to a given level and then fading up the relevant Master Control so that the result appears on stage. Lighting desk’s that have “2-Presets” enable you to set your next scene up on another set of channel controls and then crossfade that scene in when required.
More sophisticated lighting desks have a number of playback features:
Memory Playback – Stack Control and the Go button.
Even simple lighting desks have often a degree of Memory Playback which enable the operator to record “memories” of different scenes and their channel levels and then play them back using a fader or “Go” button. These scenes can be faded in and out using a pre-recording time or timed manually by the op. A lighting desk that has a “go” button plays back scenes using “sequence control”, also known as a “theatre stack”. In a “theatre stack”, each scene is played back in numbered order every time the “go” button is pressed and, as the name suggests, this system is common in theatre shows where the cue sequence should be the same every night.
Memory Playback – Submasters are Go!
An alternative way to playback lighting scenes it use Submasters. Each submaster on the lighting desk can have a memory recorded “onto” where the scene can be faded in and out using the submaster and even added to the output of another submaster memory. This gives the lighting op really hands on control and ability to mix and match the lighting states “on the fly”. The number of acutal physical submaster faders on a lighting desk is often increased by using multiple “pages” of subs that each contain a different lighting state. There are are quite a few lighting desks that have submasters in addition to stack control and a “Go” button and these can be useful for manually operating some cues such as houselights/tab warmers etc.
All lighting desks with memory playback that use a “Go” button have a degree of timing control. Recording the fade times, both in an out, with a cue mean that when the “Go” button is pressed you get a smooth timed cross fade. Some desks give the ability to have separate “Up Times” (the number of seconds for the new cue to fade in) and “Down Times” (how long the old scene takes to fade out) which can give you more control over the ways the lighting changes. Submaster controls don’t usually need much timing control as their purpose is to provide a manual fader to control the cue by hand. Timing controls on submaster playback are more desirable when controlling moving lights – more on that later. There are some manual “2 Preset” lighting desks that have a simple automated fade time associated with their master faders.
Effects Control is a feature of a lighting desk that has some kind of automated generation of lighting effects. This can simple “chases”, timed flashes of different lights or complex generation of intelligent lighting effects that would be time consuming to produce by traditional programming.
Chase effects can be triggered by a sound signal, as well as altered using different timing and chase patterns. Lighting desks with effects control use one or more seperate master faders for overall control of the effects output.
Intelligent Lighting Desks
Intelligent lights, moving or not, can have a large number of parameters that must be controlled. Although it is possible to control a DMX intelligent lighting fixture using the simplest manual DMX desk, it is not desirable. This is largely due to the fact that the complex features that an intelligent light has to offer cannot be best used running a lighting desk with no intelligent control interface. The user interface makes programming a chore and command of large numbers of fixtures becomes difficult particularly for the beginner.
The other reason that makes controlling intelligent lighting using a traditional “generic” lighting desk is the way that cues are played back. Simple conventional lighting desks use Highest Takes Precedence (HTP) playback that is ideal for controlling dimmers and light intensity. Intelligent lighting parameters such as position, colour, gobo etc. benefit from being played back on an Latest Takes Precedence (LTP) basis which makes for better control of cues and scenes. The actual difference between HTP and LTP is another article, which will appear on this site soon.
So, having established that we need some specialised intelligent lighting desk control in order to effectively program and playback intelligent lighting cues, there are some common features to all lighting desks designed for this purpose.
That is the subject of the next article in this series – Lighting Desk Basics – Beginner’s Guide to a Stage Light Control – Part 2 Intelligent Lighting.
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