When I began assisting Jeff Davis, one of our first projects was a production of The Magic Flute for Indianapolis Opera. The opera demands both fire and water effects as part of the plot. I inquired about the use of moving lights, and Davis said that, although Indianapolis Opera had sufficient budget to rent moving lights, he did not think there was time in the production schedule to program them.

The typical Indianapolis Opera technical schedule begins with an electrics pre-hang in a four-hour call Sunday evening. Electrics finishes the over-stage hang Monday morning; without any shop preparation, the average plot of 250 units takes approximately eight hours to hang and cable. During this time, scenic elements are assembled offstage and then taken onstage when it becomes available. Monday evening is a piano tech onstage with scenery, with no electrics focused. On Tuesday, we focus static lights during the day and light over the first orchestra dress rehearsal in the evening. Since Tuesday rehearsal is an orchestra dress, if the scene changes last longer than the required orchestra breaks, the curtain comes in, and the rehearsal becomes, essentially, a sitzprobe until such time as the scene change is completed. Wednesday morning is a work call for scenery and lighting. The afternoon is a lighting rehearsal, and final orchestra dress is that night. Thursday is the day off, and Friday is opening night.

In laying out a static lighting plot, Davis is meticulous about working in plan, section, and front elevation to compile a three-dimensional overview of each light and its focus. Both he and I still do this work on a drafting board simply because it is faster than trying to work in a computer, because one can overlay drawings on top of one another and ensure that information is the same between multiple views without having to constantly "zoom" in and out.

While Davis was laying out one particular show, I was reacquainting myself with the specs of the Martin Professional MAC 2000, and while reading the manual, I came across the maximum pan and tilt in the specification. If Davis can figure the focus of static fixtures, why could we not do it for automated fixtures? It occurred to me that it should be possible, using math, to break down degrees of pan and tilt for the fixture into percentage values that could be entered into the ETC Obsession 2 offline editor.

We decided to rent eight MAC 2000 Profiles to accomplish the fire and water effects needed for a production of The Magic Flute. Davis plotted on the drafting board the angles that would make the lights focus across the stage falling off at center. I made myself a math quiz, and we tried the group during the load-in. Much to our delight, the focus was very close to what we had intended, within 6" to 1', and required very little cleanup. We then programmed additional focus positions before the piano tech.

Shortly thereafter, we were lighting Hansel and Gretel for Indianapolis, with scenery by Maurice Sendak of Where The Wild Things Are fame. The scenery consisted largely of painted drops and used a large number of line-sets over-stage. Clowes Hall also has an orchestra shell, which further constricts the line-set schedule. The result was that there was room only for four electrics, but one still needed the flexibility to light translucent drops in the mid-stage zone, even though an electric could not be specifically dedicated to that task. Davis asked how confident I was in our mathematical system, and I said that I thought it was ready for prime time.

To solve the various challenges of the production, Davis used exclusively moving lights over-stage, and we were able to pre-focus the entire ML rig offline for each set. The result was that we were able to touch up the ML focus during the Monday night rehearsal, get the cue structure for the show into the console, and even write the moving lights into the show. On Tuesday, we focused the FOH plus limited onstage booms and cyc lighting in three hours. In the remaining five hours, the carpenters performed a scene shift rehearsal, during which we continued lighting. Thus, the Tuesday evening orchestra dress ran like a show.

In order to mathematically determine the channel percentage values, you first need to divide the total pan or tilt degrees from the specification by 100. This yields the number of degrees per percentage point. You then look at the focus of the light on the drawings. Say, for example, that you are focusing a MAC 2000 as a sidelight panning down 45 degrees from 50%-50%, which would be determined in plan. MAC 2000s have a maximum pan range of 540 degrees. When divided by 100%, this means that a MAC 2000 pans 5.4 degrees per percentage point. Next, you divide 45 degrees by 5.4 degrees per 1%. Hopefully you come out with 8.33%. We always set up sidelights so that there is a pan invert and one set (SL or SR) will be flipped, depending upon manufacturer, so that all lights will pan up going upstage. Since these are panning downstage, the result, 8.33, is subtracted from 50%-50%, and the resulting number is 41.66. So in 8-bit (1-channel), the result would round up to 42, or in 16 bit, (2-channel), the coarse value would be 41%, and the fine value would be 67%.

The process is similar for the tilt. MAC 2000s tilt through 267 degrees. When 267 is divided by 100% we see that the light tilts 2.67 degrees per percentage point. In this case, the unit tilts up 17.21 degrees. To find the percentage, divide 17.21 degrees by 2.67 degrees per percentage point for a result of 6.45%, which would be added to 50% for a total of 56% in 8-bit, or 56% course tilt, and 45% fine tilt in 16-bit.

Since The Magic Flute, we have used such rigs for seven productions at Indianapolis Opera, as well as numerous productions for other companies. The result in Indianapolis is that lighting has gained about eight hours of design time, scenery has gained a five-hour scene shift rehearsal, and the finished product is a lot cleaner than it used to be. During our most recent production of La Traviata, Davis remarked, "We would not have the time to design this without moving lights."

Brian Barnett is a lighting designer and associate LD to Jeff Davis. Clients include Indianapolis Opera, The St. Louis Muny, Palm Beach Opera, Gotham Early Music Society (@ The Cloisters), Cincinnati Symphony, and Barrington Stage Company.

Jeff Davis designs lighting for opera, theatre, and television, including Broadway and Off-Broadway, New York City Opera, One Life to Live, All My Children, and Live From Lincoln Center. He has three Emmy Award nominations, an LA Dramalogue Award, and a Philadelphia Barrymore Award.