Scenic projection can add new dimensions to a production and create visual effects not necessarily attainable with scenery, lighting, or props. Projection for entertainment and presentation has seen a revival over the last ten years, and the phrase, “We're going to do it with projection,” has become a source of both excitement and fear. Done well, it can make a very substantial contribution to the production, but doing it well takes time, imagination, and, of course, skill. It is no “get out of jail free card” that magically transforms a so-so design into a dazzling visual experience.
However, is it really possible to get effective scenic projection without spending serious money on large format projectors and artwork? And don't you need to have special expertise in the art of projection to even attempt this?
Well, guess what? It is possible, and, no, you don't need special training to get useful results. Now, before we go any further, it is worth pointing out that nothing comes close to the performance of a properly set up large format projector, and, if you have the budget for that kind of hardware, you would be wise to also hire a professional to get the most out of it.
Unfortunately, few productions have the budget for dedicated projection equipment of this caliber. The “dream machines” from Pani, E/T/C, Hardware for Xenon, and others are, unfortunately, out of reach for many. So, what about digital projection using video projectors? Yes, that is a possibility and definitely a technology to watch, but projectors with enough lumen output and resolution are still costly and not trivial to interface or to blend in with the stage lighting.
So what to do? Give up on projection altogether? No, not at all. Chances are good that you already have at your disposal (or can rent at a low cost) the hardware required, and a few hours later, you, too, can have the Austrian Alps framing the scenes for your next production of The Sound of Music.
A NEW GENERATION
The key to “low budget” projection is the latest generation of ellipsoidals (or profile spots, as the Europeans call them) with cold mirror optics and improved imaging capabilities. Used correctly, they are quite useable for many projection jobs and run cool enough to allow you to use them as “slide projectors,” with the actual slides being substituted by plastic transparencies or “desktop gobos,” as we might call them.
Ellipsoidals are really projectors. The differences between ellipsoidals and scenic projectors are in the details. The principle of operation is exactly the same: a light source, a gate, and a projection lens. An ellipsoidal is a basic projector, and we use it for projection using glass or metal gobos. Unfortunately, incandescent light sources produce a lot of heat, and this also gets reflected and directed at the gate where the gobo is situated. This can make the gobos warp or, at least, get glowingly hot.
The latest generation of ellipsoidals use a combination of cold mirror reflectors and more efficient lamps to get more light output and less heat. The significantly lower gate temperature not only makes the metal gobos last forever, but, with a bit of help, you can even put plastic color slides in them.
Some ellipsoidals, notably the Pacific range from Selecon, run so cool as to allow you to use desktop gobos directly. Other ellipsoidals need a bit of extra help. To this end, Rosco has come up with the ImagePro™, a holder for desktop gobos with built in thermal management. The ImagePro™ uses a clever combination of IR (heat) reflection, fan cooling, and UV blocking to keep the gobo alive and well for an extended period of time. Other suppliers, such as Selecon, offer gobo holders with a built-in heat and UV filtering glass.
So how long does a desktop gobo last? Well, that depends on the type of fixture used, the lamp wattage, and the type of image, but 25 to 100 hours is typical. It should be noted that even the cool running Pacific range from Selecon can make good use of the ImagePro™. This extends the useful life of the desktop gobos even further.
VERY LONG LIFE PROJECTION
If you need more than a hundred hours of useful life out of your projections, get the image made into a full-color glass gobo. This is not cheap, but if your production is a success and will run for some time, it is probably cost effective.
Nevertheless, the use of desktop gobos allows you to try ideas and experiment at a very low cost before committing to more permanent media, such as glass gobos.
If you are planning to use projection for an exhibition or other applications where dimming is not required, you should consider using metal halide ellipsoidals. ETC, Strand, and Selecon all offer 70W and 150W metal halide discharge versions of their popular ellipsoidals. The 150W models roughly equate to a 575/600W tungsten version, in terms of light output, but with much reduced heat generation. For these fixtures, there is also a choice of lamps of different color temperatures, typically 3000K and 4200K. It is reasonable to expect the life of your desktop gobo to last closer to 1000 hours or more when using them in this type of fixture.
The other major improvement of the modern ellipsoidal is the use of better, more sophisticated lenses. While the former generation of ellipsoidals often used off-the-shelf, plano convex lenses, the current generation invariably uses computer-optimized, custom designed aspheric lenses with multi-layer coatings — basically, the same technology that manufacturers of camera optics employ.
The result is a vast improvement in imaging quality, with greatly reduced color fringing, better contrast, and pretty consistently maintained focus across the image.
Any image can be used to create a projection, and desktop gobos are no exception. Create your own unique image from scratch, or use an existing one. Digitally created images are the easiest to work with, but, obviously, any image can be scanned into digital format for further processing. There are also a growing number of projection-ready desktop gobo images available from companies like Rosco, Fergo, and others.
So, why is it necessary to modify the image before using it in your projector? Well, a good-looking print does not necessarily make a good-looking projection. In most cases, both contrast and color saturation must be increased to ensure the image does not look pale and washed out. This is particularly important if the original is a digital photo, since cameras often overexpose the image.
You will probably also need to change the size and format of the image to suit the surface on which you are projecting. You may use an ellipsoidal with zoom optics that allows you to resize the projection but does not allow you to change the aspect ratio of the image.
Fortunately, Rosco has produced an excellent step-by-step guide to this process, and it can be downloaded from their website at www.rosco.com.
To create a plastic transparency for use in a cool beam ellipsoidal, you only need a desktop computer, an inkjet printer, good quality overhead transparency film, and some software that allows you to modify the images, typically something like Paint Shop Pro or Adobe® Photoshop®. The former can be bought for as little as $100 and will be more than enough for the job. The Fergo website offers some very good advice about printers and materials (See Resources).
PROJECTION SET UP
Ellipsoidals are generally used with a beam that has a field that is more intense in the center, a.k.a. “cosine distribution.” This makes it easier to get adjacent beams to blend together to create even coverage over a larger area. However, when using an ellipsoidal for projection, the field must be as flat as possible. Ideally, the beam should have the same intensity at all points. This makes the projected image look the best, and it also helps the gobo or plastic transparency survive for more than a few hours. You must set your fixture to flat field before you put the plastic transparency in. An incorrectly aligned ellipsoidal can burn through a desktop gobo very quickly.
FINDING THE SWEET SPOT
When you have determined what beam angle you need to get the required size for your projection, you must carefully consider your choice of fixture. Projection optics with zoom capability have a sweet spot where you get the best possible imaging. This also holds true for zoom ellipsoidals. Let's say you need a beam angle of 30°. You will, most likely, find that the 15-40 zoom gives better results than the 25-50 zoom when both are set to 30°. The sweet spot is usually found at the narrow end of the zoom range. This is something that you need to try out in practice, as no manufacturer we know provides this kind of information.
CARE FOR A DONUT?
The imaging quality of the ellipsoidal may be further improved by inserting a mask in the color frame position. This device is commonly known as a “donut.” The donut looks like a color frame with too small an opening, typically half the diameter of the color frame opening or smaller. So, how does it work? Put very simply, it blocks out stray rays of light that otherwise would diffuse and dilute the image. The result is improved focus and contrast at the cost of some reduced intensity. The positive effect of a donut is more pronounced with the older generation of ellipsoidals, but even the new and improved fixtures can benefit from a little tidying up.
You can buy donuts as an accessory or cut your own out of GAM Blackwrap™ foil and mount it in a color frame. This also enables you to experiment with the size and form of the opening.
Sometimes, the shortcomings of a simpler optical system can work to your advantage. The projection of abstract images can benefit from optical distortion, making the final projection more expressive and interesting. Take some time to experiment with various types of images and ellipsoidals and learn what works best for each purpose, and you will be better prepared to deal with each task.
Who says a projected image must work in isolation? Try layering images using multiple fixtures, or combine your special desktop gobos with standard gobo patterns. In some fixtures, it is even possible to use both a desktop gobo (typically, in the iris slot) as well as a regular metal or glass gobo in the normal pattern slot.
Another trick is to add a scroller to the ellipsoidal projector, adding color to the desktop gobo. This works particularly well with monochrome images — go from cold blue to sepia to lavender.
SAFETY IN NUMBERS
Probably the most common problem with projecting is getting a wide enough image at the available projection distance. Wide angle projection lenses are available for dedicated projectors, but, with ellipsoidals, you will find that nothing gets you the required projection size without serious distortion of the image, and, in any case, the intensity will most likely be too low.
The second most common problem is getting the image bright enough. Unlike a movie theatre, your projection has to fight for attention against a large number of ambient light sources (ie, the rest of the lighting rig). The solution to both problems is to use multiple projectors, each set to the best possible imaging and carefully adjusted to create a common image.
Having to use a number of low cost ellipsoidals, rather than a single proper scenic projector, can work to your creative advantage. Multiple projectors make it possible to change individual parts of the projection while keeping the overall image in place. This opens up many interesting creative possibilities. Another issue is that a single projector, no matter how sophisticated and powerful, can only cover one surface effectively. With a number of smaller projectors, the projection can be tailored to the surface, be it straight, curved, rectangular, or irregularly shaped.
The basics of projection are beyond the scope of this article, but you will probably want to learn more about it when you start experimenting. Projection is addictive! We recommend the book Projection for the Performing Arts by Graham Walne (ISBN 0-240-51390-8). It is a good primer on projection with many practical suggestions and illustrations.
BEEN THERE, DONE THAT
Some of you may already have tried these desktop gobo techniques, probably with varying results. Some love it; some think it is not so great. The key to successful projection using ellipsoidals, in general, and desktop gobos, in particular, is to understand the limitations and how to properly create the transparencies. Spending time with image enhancement using Photoshop or similar tools will make a huge difference to the end result. Selecting the right fixture and setting it properly also impacts the end result in a significant way. It is also important to understand that you will not get the resolution and image quality of a $50,000 large format projector using a $500 ellipsoidal, no matter how much care and thought you put into it, but it is a useful tool for small to medium sized productions and also a good introduction to projection.
Give it a try. You just might get hooked!
Mats Karlsson is a true lighting fanatic as well as sales manager at Bellalite Ljusdesign AB in Sweden. He can be reached at firstname.lastname@example.org.
Fergo Plastic Projections: www.fergo.com.au
GAM Products, Inc.: www.gamcolor.com
Hardware for Xenon: www.hardwarexenon.com
Paint Shop Pro: www.jasc.com