4

Basic Programming

Programming automated lights is essentially the data entry of specialized instructions into a custom computer application. This data is then transmitted via a unique protocol to robotic lighting fixtures. While this appears as a simple process, there is much more involved than simple data entry. An automated lighting programmer must be familiar with the particulars of the lighting console, the fixtures, the production, and the lighting designer. With a basic understanding of each of these elements, a programmer is able to properly create the lighting programming required for any production.

Understanding Your Fixtures

I can get inside my car and drive it to the airport; then I can get inside a rental car at my destination and drive it with ease. The steering wheel, gas, and brake pedals, etc. are all in the same location and have the same functions as all other cars. In Australia I drove a right-handdrive car and had to learn the differences, but the elements still worked the same (steering, braking, etc.). Moving light programming generally is not as easy as driving a car. This is because there are no standards when it comes to how fixture parameters should respond to DMX.

Imagine if steering one car you just used the steering wheel, then another type of car you had to turn a knob to adjust the steering wheel mode between turning mode, straight mode, and skid mode. Yet another type of car required turning the steering wheel, adjusting the knob, and pressing on a pedal to adjust the speed of the turning. It would be very difficult to adjust from one vehicle to another, without first studying the method of steering. This is the case with many automated lighting functions!

Many hard-edged automated fixtures have rotating gobos. The number of DMX channels used to select and rotate a single gobo can range from 1 to 5 depending on fixture type and DMX mode. Because of all the differences, most lighting consoles simply apply the DMX protocols of the fixtures to adjustable parameters. This can lead to much confusion when programming as it requires the programmer to be familiar with the particularities of each fixture’s protocol.

It is imperative that you study the DMX protocol of each fixture type within your lighting rig so you understand the capabilities and functions of that particular unit. Without this basic understanding, you will spend most of your time trying to figure out how to “drive” each fixture. Just because you know how to rotate gobos with one type of fixture does not mean you can do the same with others. Prior to beginning programming you should read the DMX protocol of each light and then test its functions. I suggest downloading the manuals and protocols of fixtures before you even arrive at the production site. In addition, you can use most console’s offline editors to determine exactly how the fixtures are implemented into the console.

Although every fixture is different, there are some common guidelines as to how most professional automated lighting fixtures function. Below I have listed the common parameters and their usual functions. Please be aware that both console and fixture manuals might refer to these items with different terminology.

Pan and Tilt—Controls the movement of a mirror or moving head. Typically 2 channels are used for each parameter to create 16-bit accuracy.

Intensity—Usually 0–100% will control the output of the fixture.
Note: some manufacturers place additional parameters on this channel such as strobe or control.

Color Mixing—Cyan, Magenta, and Yellow are variably controlled via 0–100%, with zero equal to no color and 100% full color. Some fixtures are reversed or will contain additional fixed colors on the same control channel.

Fixed Color—Certain values on this channel will recall specific colors from a color wheel. Other values may recall half or split colors. In addition there are usually premade spins of the color wheel at different speeds to select from this channel.

Frost—0–100% provides variable control of a frosting or softening of the output. Usually zero is equal to no frost and 100% full frost; however, some fixtures are reversed or may contain additional frost strobing effects.

Shutter Strobe—This channel will control the shutter of the fixture. The shutter will normally be open, with an option for closed. In addition, various types and speeds of strobing will be available. Some manufacturers also place control functions on this channel.

Control—The control channel often contains all nonstandard programming functions. Lamp on/off, fixture shutdown, fixture reset or home, and other specific functions are accessed from this channel. Usually a modifier (strobe channel closed) and/or a time value (hold at a value for 5 seconds) is required to prevent accidental triggering of control functions.

Fixed Gobo—Certain values on this channel will recall specific gobos from a nonrotating gobo wheel. Other values may recall half or partial gobos. In addition, there are usually premade spins and/or shakes of the gobo wheel at different speeds to select from this channel.

Rotating Gobo—Certain values on this channel will recall specific rotating gobos from a rotating gobo wheel. Other values may recall half or partial gobos. In addition, there are usually premade spins and/or shakes of the gobo wheel at different speeds to select from this channel.

Rotate Speed—Most manufacturers use an additional channel to adjust the speed of rotation for the rotating gobo wheel. Depending on the fixture, this channel might also select the mode (indexing, rotate forward or reverse) of the rotating gobo.

Iris—This channel will adjust the iris of the fixture from a small size to full open (or vice versa) when adjusted from 0–100%. In addition, the channel might include premade iris strobing and effects.

Speed—Many fixtures include speed channels to allow for fixture control crossfades of values. This functionality is used to create smoother transitions than is possible by most DMX controllers. See below for further information on speed channels.

Mode Channels—Sometimes a manufacturer will add mode channels to their fixtures. These channels are used to modify the functionality of another channel. For example, a color mode channel will change the behavior of the protocol for the fixed color wheel. The normal mode for the color wheel might be to select fixed colors as the value changes from 0–100%. If a different mode is selected from the color mode channel, it will change the fixed color channel so it will spin at various speeds from 0–100%. Yet another mode might spin the wheel the opposite direction, or allow for oscillating between two colors at different speeds. Mode channels are commonly found for color wheels, gobo wheels, and rotating gobos.

There are many more parameter types depending upon your fixture type. Refer to the fixture’s DMX protocol documentation for exact details on all parameters. If you are unsure as to how a particular function is controlled from your lighting console, it is best to experiment with some test cues.

Speed Channels

DMX is a simple protocol that was developed to control lighting dimmers. As automated lighting developed, it latched onto this protocol as a uniform standard for lighting control. However the resolution offered by 256 values per channel is rather limiting. Most manufacturers found they needed a higher resolution for pan and tilt. By combining two DMX channels to control a single parameter, they are able to achieve 65,535 values per parameter. This is referred to as 16-bit DMX control and is commonly used for pan and tilt as well as rotating gobo indexing.

With very slow movements of fixture parameters, 256 or even 65,535 values are not enough. If you have ever tried to move a parameter extremely slowly (2 minutes or more), then you have probably noticed a shaky or steppy movement. This is because the resolution DMX crossfading is less than adequate in these situations. For this reason most manufacturers of automated lighting have provided a timing parameter to achieve higher resolution movements. Now instead of stepping between a value of 10 and 22 across 2 minutes via a DMX crossfade, you can tell the fixture to move from one position to another in 2 minutes smoothly. The console instantly sends the new value and speed timing to the fixture, and the fixture moves the parameter at the selected time with a much higher resolution than can be achieved via DMX. This usually results in smoother parameter movements.

So how do you use these magic-timing parameters? Well, that really depends upon your fixture, so it is back to reading the DMX protocol for you. First, however, you need to know what to look for as each manufacturer has different names and types of speed controls. Some of the names are Mspeed, Vector Speed, Beam Time, Focus Time, Color Time, Speed, Vector, and Xfade. The names might be different, but there are some similarities in programming these timing functions.

The first rule is that if you are not going to use the timing functions, ensure that you have the channel(s) set to their off setting. This is not the same as the fastest speed setting, but a different value that disables the internal timing of the fixture altogether. The speed controls of fixtures are often broken down by type of parameter (beam, color, pan/tilt, etc.). On the other hand, some manufacturers provide one universal speed parameter and then allow the programmer to select which parameter will be affected by the speed channel. For example, the DMX protocol of the channel used for gobo selection might have all 6 gobos in crossfade mode and then all 6 gobos in speed mode (see Table 4.1).

Table 4.1 Sample Gobo Channel DMX Protocol

Selecting gobo 2 from either section of the protocol will yield the same image on stage; however, the speed mode version will respond to the speed channel timing. When selected with speed timing on, the gobos will scroll into their position in a time defined by the speed channel. Without this setting the gobos will either jump directly to their new setting or follow the console’s crossfade time. Always refer to the user’s manual to see how specific fixtures function.

If the desired effect is to change from one gobo to another in time of 2 minutes, you would select gobo 2 (possibly in speed mode), then set the speed channel (possibly the beam speed) to 2 minutes. Now you must ensure that your console does not try to crossfade the value for the gobo channel or the speed channel. The best thing to do is to assign the gobo channel and the speed channel a crossfade time of zero (or set the entire cue time to zero). If you were to crossfade either of these two parameters, you would confuse the fixture, as it would try to calculate the movement speed while the desk is crossfading. The result would be a movement much slower than you intended.

To avoid having a separate speed channel for each parameter of the fixture, the manufacturers have given us either one speed channel, or several categorized speed channels. This means that when you assign a gobo to change in two minutes, this might also affect other beam parameters or even pan and tilt. This is where you need to study the manual again to determine what options you have. Some fixtures have options on controls or other channels to disable speed functions from pan, tilt, etc. In addition, with tracking consoles you need to be aware of when you have turned on the speed channel. You might need to turn it off for the next cue. If you forget to turn it off, then it will remain on for the rest of your show and possibly wreak havoc with all your future crossfades. In addition, if you try to manually move the fixture or its parameters, it might take two minutes to change from one gobo to the next.

Timing and speed parameters are not used with every cue, but they are a handy tool that allow for smooth, slow transitions and changing of parameters that might not be crossfadable. It is extremely important that you study your fixture’s DMX protocol to determine exactly how these speed functions relate. Each manufacturer has their own methods, and often these can change between fixtures. Then be sure not to crossfade and use speed channels at the same time. Finally, ensure you disable the speed functions when they are not needed. These powerful functions are often misunderstood and underused; however, with a little reading and practice, they can be easily mastered.

Palettes

Once you have patched the console, created groups, and become familiar with your fixtures, you should begin building position palettes. Depending upon your console, these might be referred to as palettes, presets, memories, etc. These are references used to quickly select common positions used when programming. Most programmers take the time to build positions that they feel will be used within the production. Once the positions are stored in the console, they are available for instantaneous recall, without having to move fixtures manually into position. In addition, if your cues refer to the palette (instead of pan and tilt values), then you can update the palette values and the cues will simultaneously update with the new information. This can be a lifesaver when the director decides to move an acting area upstage by two feet. You simply adjust the fixtures in that position palette and all your cues referencing the palette will be corrected. Position palettes are commonly used in touring productions as the lighting rig rarely hangs at the same height and location relative to the stage. Palettes allow for the updating of only a small number of positions instead of a large number of cues.

First, look at the stage and try to determine common positions for the fixtures. If the show has a band with a singer, guitar player, bass player, and drummer, then these would be obvious positions to build. It is best to focus every fixture in each of these common positions. That way, if the LD asks for fixture #28 in the drummer position, you can quickly select the fixture and the position. Even if you are programming a one-off type show and do not plan on using the updating features of palettes, they will be extremely useful when building cues. By spending a few hours building position palettes, you can save many more hours when programming, as you do not need to move each fixture individually for each cue. The cue building process is made simpler by allowing you to select very quickly the common positions for the fixtures (see Table 4.2).

Table 4.2 Common Position Palettes

In addition, building color and gobo palettes can produce the same benefits. In the same manner as building position palettes, most desks allow for the creation of palettes with any parameter of the fixtures. Imagine having to continuously color mix the same shade of blue for each cue! A color palette allows for instantaneous selection of this color. Then if the LD or director of the show decides the blue is too pale and asks you to change all cues using that color of blue, you simply update the palette and not each and every cue. Once again programming and editing will be accelerated due to the ease of palette selection and modification. For example, if the LD asks for “fixture #19 upstage center in red with the cone gobo,” you could achieve this in a few simple keystrokes.

Prior to building palettes, it is a good idea to home (or recalibrate/ reset) your fixtures. If the fixtures are out of calibration when you build your palettes, then the palettes will be misaligned after the fixtures are recalibrated (or even powered on and off), causing you to have to touch up your palettes.

Some other palettes you might want to consider building are iris, frost, intensity, and fixture homing or shutdown. The more palettes you premake, the less time you will spend in cue creation dialing through values. However, do not allow this preparation to get out of hand, as you do not want to spend all your time building palettes and groups.

Quality is often better than quantity, so it is suggested that you only create the groups and palettes that you think will be used with the production. The more palettes you have the more that will need updating in the future. In addition, a large number of palettes can slow down your programming if you have to search through hundreds of palettes to find the desired position or color. A good programmer will discover the perfect amount of palettes for each situation. Some productions will require hundreds of palettes, while others only a few. Your ability to determine the essentials for each production while also maximizing the output potential of the fixtures will aid the LD’s overall process in creating a successful production.