There are many concepts and principles every automated lighting programmer should know. The most important is probably the principle of “tracking.” It is actually a very simple concept, yet is often the most difficult to teach and learn. However, once tracking is understood, its impor-tance to automated lighting data becomes clear.
Recording Changes
Simply put, tracking is the result of a console recording only the changes to parameter values instead of a complete stage picture. Before I explain the details of tracking, it is important to examine why it was created. Originally, lighting consoles controlled just dimmers, and inten-sity was the only parameter ever used. A console would be set up with a specific number of intensity channels, and each cue would record a value for all the channels in the desk. This worked wonderfully to ensure that when a cue was played, the look (or state) on stage was always the same.
When automated lighting entered the industry, the first round of controllers was based on this same idea. All the attributes of all the moving lights in the controller (usually no more than 24) would be recorded into each cue. So, if you had a series of cues that changed the color of your fixtures but not the position, then every one of these cues would contain position information (as well as all other parameters).
While this was great for dimmers, for automated lights it presented new problems. After the first cue was created with position, intensity, color, etc., all subsequent cues had to be based on a copy of this first cue to ensure all the parameters were the same. If you later needed to change the gobo in the cues, all the cues would need to be edited. It became apparent rather quickly that a new method of storing and recalling parameter data was required.
The Birth of Tracking
As the industry grew, a new way of working with fixture data was needed. Many early consoles had different names and display processes, but they all were versions of tracking consoles. I remember that the terms “transparencies,” “matrix” and even “selective record” were used in the dif-ferent consoles as a means of referring to what we now call tracking.
As stated above, tracking is a process of recording into cues only the changes to parameter values, instead of recording the entire stage look. Lighting consoles still present this data to the user in different manners, but now modern consoles all use various text colors and indicators to make it clear to the programmer where tracking occurs. Refer to your console user manual for further information.
Tracking in Action
You can see tracking in action in Chart 1. Values indicated in red text are actually recorded into the cues. Values indicated in blue text are tracking from a previous cue. For instance, in Cue 1, Fixture 1 is recorded at 100% in gobo 1. Cue 2 does not contain any data for this fixture, so it tracks its value from Cue 1. In fact, Cue 2 only contains data for Fixture 2 and will not alter the look of any other fixtures on stage. The combined effects of tracking and recorded data (both the blue and red text in Cue 2) are known as the “state” of the cue. So while the data in Cue 2 is only for Fixture 2, it has a state for all fixtures based on values that track into the cue from Cue 1.
Looking further at the example, you can see that Fixture 3 tracks its values (75% and gobo 3) into Cues 2 and 3. Here you can see one of the great advantages of tracking. If you change the data in Cue 1 to 50% with gobo 2 for Fixture 3, then this new change will also affect the state of Cues 2 and 3 because the change will track through just as the previous values did. So an advantage of tracking is that you can change a single cue and have the change automatically track through subsequent cues. However, you should also use caution, as this can be very confusing. What if you did not consider tracking when you changed Cue 1, as described above? You might be surprised that when you play Cue 2, you will find that the fixture is no longer 75% with gobo 3, but has “taken on” the change made to Cue 1. This is because the values have tracked from Cue 1 to Cue 2.
The Power of Tracking
As you can see, tracking can be extremely useful. Imagine creating 50 cues all using the same position, intensity and focus for several fixtures. During these cues, the colors change, but nothing else changes. Suddenly you are asked to alter the intensity throughout this se-quence. Instead of needing to edit all 50 cues, you can just apply the edit to the fist cue, and this change will track into all the subsequent cues!
Of course this takes organization when you are recording your cues. In order for this example to work, you must not have recorded inten-sity values into any of your cues (except the first one). If, for instance, you had recorded the same intensity values as Cue 1 into Cue 24, then the edit to Cue 1 would only work until Cue 23. At that point, the recorded value for Cue 24 would be played, and your edit lost from that point forward. On the other hand, if you want to end the sequence of tracking, you can purposely record a value into a cue and thus create a block to the tracking. Any time an actual value is recorded for a parameter, tracking will cease to occur, as the recorded value will always take precedence.
When I am working with a large cue list for a production, I often create “block” cues to stop values from tracking into various sections of cues. For example, when I’m working on an ice skating show, I create a block cue at the beginning of each skater’s act. This way, absolutely no values from a previous act can track into this skater’s act. A block is made by recording values for all parameters of all fixtures. Because this defines the start of each skater’s set of cues, I know that I can edit cues within each skater’s range and not affect any subsequent cues that do not relate to the particular section of the show.
Imagine if two skaters in a row used a blue color on the ice, and I had allowed this information to track from the first section to the second. Then, I decided to change the first skater’s ice color to red. Because of tracking, this change could affect the next skater’s cues too. This is why I always create block cues, so that I can use tracking within each section of a show, yet not throughout an entire cue list as a whole.
Training for Tracking
Tracking, of course, can do much more for you, including confuse you further. A full explanation of tracking takes much more than this short article, but with some practice you can learn to master tracking of data on your console. As always, refer to your console user manual to determine the text display and features related to tracking. Just remember that tracking consoles only record and playback changes to a cue, not the entire state of the stage. Then you can take full advantage of all the abilities tracking presents to you.
You can contact Brad Schiller by e-mailing him at bschiller@plsn.com.
