The Basics
Although every luminaire with shutters operates slightly differently, they all include the same basic principles. Typically, you will have four blades that you can bring into the gate (image area) to crop unwanted output. The blades will not only move in and out of the beam, each blade usually has an adjustable angle as well. This enables you to create more than basic squares and rectangles, because each blade can be assigned to various degrees of angulation. Additionally, the entire shutter mechanism consisting of the four blades and their angling abilities can be rotated for even better alignment of the shutter cuts on the projected surface.
When programming a luminaire with shutters, you will find that you have nine individual parameters to control — including the four blades, each blade’s angle and the mechanism angle. This equates into quite a lot of knob turning and data to keep up with per fixture. If you have lots of fixtures that require shutter cuts, you need to allocate an appropriate amount of time to complete the tasks. For instance, I often have 20 or so fixtures lighting the set of an annual corporate event. Every single fixture needs shutter cuts to ensure that the light falls only on the designated walls and not on the floor or video projection screens. I know that the initial setting of the shutter cuts will take a considerable amount of time, and I work this into my programming plan.
The Actual Programming
Working with shutters is really not much more difficult than working with any other parameter, but it can be daunting due to the number of controls that all interact together and yet can also alter the results of each other. When I am working with shutters, I will first adjust the lens focus so that I am focused on the shutters. That lets me to see exactly what I am working with. Next, I will select the first fixture and begin to adjust a shutter. Deepening on your console, lighting plot, fixture type, and current fixture positioning, you might have to determine which shutter is in which position. It is very difficult to always be certain which shutter controls the “top” or “right” shutter cut due to all the previously mentioned factors.
Once you have oriented yourself with the shutter positions, you can begin to work with one shutter to crop the output as desired. If you need to angle the shutter cut, begin with the shutter’s angle control first instead of the entire system’s adjustment. If you cannot achieve the needed cut, then alter the system’s angle. Once you are happy with the first shutter cut, move on to the other cuts for this fixture. As you continue through the cuts, it may become apparent that you need to alter the pan/tilt position or zoom setting to create the required output.
Once you get the shutters, pan/tilt, and zoom set as need, it is essential to store this information into palettes/presets. This way you can come back and quickly select or update them easily at a later date if needed. It is never a good idea to simply store framing shutter data into cues without using a palette/preset. Due to the complexity of shutters, I will often store/merge my data into the palette/preset as I am working with each and every unit instead of adjusting them all first and then storing. This helps by protecting the data as I work with multiple fixtures. It is also useful to store a combined palette that has the pan/tilt, zoom, edge, and framing shutter values for quick recall of the exact position and adjustments.
Console Tools
As stated above, many consoles simply implement control of framing shutters as they do any other variable parameter. This means that you have nine different parameters to adjust for the shutters. Most consoles do not have nine encoders, so you will find that you need to cycle through the encoder pages to adjust all the different framing shutter controls. As you continue to make changes to a fixture’s shutters, this can result in lots of button pressing as you cycle through the shutter controls. Some consoles even add additional shutter parameters that simultaneously adjust top/bottom and left/right shutters. These are very helpful, but this also adds in an additional four shutter control parameters (as each pairing also has associated angle adjustments).
Some newer desks allow you to make your own banks or pages of parameters, which can reduce or eliminate the paging requirement, and they also provide you with quick keys to the shutter controls you need in a given moment. Others go further, with fancy touch screen controls that emulate the shutter cuts on the screen. With these, you can literally slide the shutters in/out and angle them with your fingers on the monitor. This approach provides you with a graphical interface and a simpler method of control. However, the actual shutter adjustments may not be calibrated with the real fixture, so your results on screen may vary from that of the stage. Some clever consoles provide an alignment function that allows you to simply rotate the view on the screen to match that on the stage (on a per use basis). Furthermore, the angle of the fixture, pan/tilt position, projection surface and more also all come into play and affect the difference between the virtual shutters on your monitor and reality on stage. Regardless, a graphical interface is a very nifty way to adjust shutters, although I find it sometimes difficult, as I have to continually look between the screen and the stage. I much prefer turning encoders while watching the true result.
More Than Cropping
Framing shutters are typically used to crop unwanted light from the beam. However, they can also be used creatively in many other ways on stage. Some manufacturers allow their shutters to move all the way across the beam, and this can create a curtain type reveal or blackout instead of using the dimmer. Framing shutters chases (where the shutters are continuously moving in and out randomly) add a level of dynamic movement and changes that differs from rotating gobos and irises. In fact, framing shutters can be used as “customizable” gobos for both projection and aerial use. I often will make a thin rectangle from the shutters and use it either as slashes on a background or a powerful aerial beam. When you add in a rotating prism, the look becomes even larger and more exciting.
Putting It Into Perspective
Framing shutters are extremely useful tools when included in an automated luminaire. Being able to remotely block out sections of light or change the shape of the output is very powerful. Every system is different, and while some are near perfect, others have pincushion or focusing problems related to the fixture’s lenses. Furthermore, programmers must understand how the fixture and the console present the shutters and allow them to be modified. As always, be sure to read the user manuals to determine exactly how your gear operates. With framing shutters in your fixtures, you can alter lighting in amazing and creative ways. Have fun framing in looks on your next production!
