Technology: Lighting control, a brief history
Technology: Lighting control, a brief history
Elation’s Bob Mentele reflects on the evolution of lighting control systems
Today, lighting control can be as easy as saying, ‘Alexa, turn off the table lamp’. We may take for granted the fact that when we raise a fader on our console or computer screen, all of the lights fade up, move and change colour at our command. Simplified lighting control and manipulation has become second nature to us, but it certainly wasn’t always that way.
Electronic lighting control first made its appearance in the late 1950s. The biggest change that made this possible was the development of electronic dimming technology. Before that was created, control of a lighting system relied on physical resistance dimming systems and, most often, a team of men to run them. The new electronic systems used an analogue control method, typically a 0–10V signal. This signal was attenuated, or modified, using a series of sliders or faders on a control board.
The level of attenuation had a direct impact on the 0–10V signal, which was then interpreted by the dimmer into the output power level to the lighting fixture. Eventually, designers created what is called a two-scene preset board. These consoles consist of two banks of faders, one for each ‘scene’.
The two banks each contain a fader for every dimmer in the lighting system. The lighting settings can be adjusted and set in one bank, and the other bank allows for the operator to preset the settings for the next scene. When it’s time to switch scenes, the operator simply has to adjust what are called ‘crossfaders’. These are a pair of inversely proportional faders.
One is at full intensity when in the up position, while the other is at full when in the down position. When the operator moves these two faders, the corresponding scene fades in or out, depending on the direction the crossfaders are moved. The crossfaders can also be moved independently of one another, allowing for a variety of fade effects by the operator.
While this allowed for much more creative control of a lighting system, it still took an operator time to preset the following scene. If a series of scenes needed to occur rapidly, it would be difficult to achieve. Eventually, an expansion of the two-scene preset was created. It was referred to as a preset panel. This system was based on the same concept as the two-scene but allowed for as many as 10 different scenes to be set in advance.
The system would be controlled by two operators – one would set the scenes at the panel while the other controlled the operator’s board, which had a bank of buttons to assign scenes to different crossfaders. This system was not nearly as common as the two-scene preset due to its size and cost. Two-scene preset consoles are still available today and make a great, low-cost option for small or non-complex lighting systems.
As computer technology became more affordable, lighting companies began to develop computerised controllers. These controllers allowed for all of the lighting presets to be set beforehand and recalled later when needed. The first version of these consoles used punch card memory systems. The lighting was manipulated by an interface with faders and buttons, similar to how we control them today. When the lighting was adjusted, a punch card would be created to allow for future recall.
Each preset in the show had its own punch card. When you needed to change the preset, you simply inserted a new card, which set the levels for the following scene and the crossfade could occur. A large show could have hundreds of presets, so hundreds of punch cards as well. But it allowed for more complex show control.
In the 1980s, digital memory became available, so lighting consoles could store multiple presets onto a disk for future recall. A full show of lighting presets could be stored on one disk and loaded when needed. If the show was large, sometimes two disks would be required and, at a halfway point in the show, the second half of presets would be loaded into the console.
Even through all this innovation in control interfacing, we were still relying on a 0–10V analogue signal to transmit the information. The other issue was that the actual 0–10V signal was not standardised. Some manufacturers used other voltages, or polarities, so interfacing one company’s dimming to another company’s controller was difficult or impractical. In the mid 1970s, a standard 0–10V signal was agreed upon so cross-compatibility was possible.
One big downfall with this method remained: using 0–10V required a wire from the console to every individual dimmer. As systems grew larger, that became quite a complex infrastructure to maintain. In the 1980s, a technology called multiplexing was developed. Its primary use was in the communications industry, but lighting manufacturers were able to use it to send lighting control information down a two-wire (plus ground) cable. This helped to get rid of the large infrastructure required for 0–10V control. But each manufacturer created its own version of the protocol, so we again ran into issues of interoperability. Although the size of the cable required to send the signal decreased, we were still limited on the size of system that multiplex could support, typically 96 channels.
Later in the 1980s, it was decided that we again needed a more universal control protocol that could also handle the larger lighting systems that were being created. The Engineering Commission of the USITT (United States Institute for Theatre Technology) organisation developed and released the DMX512 protocol in 1986. It has since been revised and updated, but the basic framework remains the same today. DMX is a digital signal, so it can include more information than previous methods. One cable of DMX can transmit a ‘universe’ of data. One ‘universe’ of DMX contains 512 channels of control.
The use of DMX coincided with the development of various intelligent, or multi-parameter, devices in a lighting system. A dimmer is a single-parameter device, so it occupies only one fader or control channel. Other devices like LED fixtures or moving lights are multi-parameter devices as they require more than one channel of DMX to control. With those additional channels also comes the need to have, seemingly, a more complex lighting control interface. In reality, that complexity saves us time and effort when controlling all of the various features we may need.
The lighting console has evolved from a large bank of faders that control each individual light to a large interface of buttons and encoders. This type of interface makes it easier to manipulate complex parameters like the movement of a fixture or the fine colour adjustment of an LED. Faders cannot be as precise as we need for those fixtures. But the learning curve to fully understand the control method of a lighting console is becoming steeper. Some manufacturers have used our familiarity with touchscreen interfaces to create more graphic and interactive control devices. Lighting consoles now come in all shapes, sizes and capabilities. The options are endless, and it can be quite daunting trying to decide what type of lighting console would work best for you and your facility.
In the next issue, we will take a look at the various options in lighting consoles today, and how to go about choosing the right one for your facility.