Custom Glass Gobos: A Primer

You see them everywhere: colored glass gobos, patterns, templates. Whatever the term, they are all the rage — in live performance, retail, and other applications. Originally too expensive for the masses, gobo prices have started coming down, making them accessible to users with modest budgets. However, with these products, clients can, and must, take an active role, helping gobo companies produce the best products. This is one case where the end result is really in the client's hands.

IMAGE QUALITY, COLOR, AND CHOICE OF FIXTURE

Many factors affect the look of a projected image. First, there is the artwork used to create the gobo. Most customers don't realize that a website capture or third-generation fax image will result in a poor gobo. Rick Hutton of Dallas-based InLight Gobo says, “There are still many clients who don't understand that the better the resolution artwork we get up front, the better the end result.” Clay Powers of Vari-Lite agrees: “The gobo is only going to be as good as the artwork it is made from. For the super-high-resolution process we are completely limited by the artwork. We get faxes, e-mails, and scans of photos. We probably spend 70% of our time trying to get the best artwork.” Be warned: Artwork should be presented in a clean, crisp image and in a format that the gobo maker can easily access. Every leading custom gobo manufacturer has a website that clearly explains the different preferred formats.

Even more complex is the issue of color. Every corporate client wants exact color-matching of its company logo. However, projection is a far different medium from print. Nearly every gobo manufacturer uses the CMYK system of color rendering, a form of color separation that allows you to match virtually every color. However, says John Hunter of Apollo Design Technology, “When the artwork comes in and we are asked to match Pantone colors, and then we go to dichroic glass, and project it on a wall, with ambient light around it, there are going to be differences in colors. A client will get a gobo and look at it on a light table and it matches their original color. But put 500W behind it, add in the background, and there are going to be differences.”

Hutton says, “They have specific Pantone numbers for print work and we can reproduce those colors, but the real problem lies in the lighting instrument. Clients will often use arc-source luminaires that have high blue content and not much red, so you lose a lot of the color-mixing and even distribution that you get with tungsten. Tungsten has more red, but you get a better balance of the colors in it.” Josh Alemany of Rosco Laboratories adds, “Most custom gobos are now made for corporate clients. They don't understand that if you have an HID source and your logo has a lot of red in it, the HID source has very little red in it. If the lamp has 150 hours on it, then it has a massive amount of green in it.” The result will not be a faithful color reproduction.

If you are using the same image in multiple projectors, this can really become an issue, says Hutton. “Different lamps, different color temperatures, and different tolerances in dichroic glass leads to slight variants in color — sometimes from image to image.” Powers says, “If you make a dozen or two dozen of the same gobo and you put them in two dozen fixtures — especially with HID sources — the colors can vary a bit.” He does add, however, “In the majority of cases the clients doing this are now more sophisticated and take a lot of this into consideration in the design.”

Which brings us to the source of the projection, the lighting unit itself. The type of projection and the detail and resolution of the projection are all affected by the choice of fixture. This is especially true for complex, expensive, high-definition custom glass gobos. Hutton says, “Some higher-resolution images are too much for some fixtures' optics to focus on. You get a small portion in focus and the rest is fuzzy; people don't always understand that it isn't caused by the gobo.” Some basic ellipsoidal fixtures don't have the right optic trains for high-resolution gobos. Hutton adds, however, that “fixture manufacturers are working to get more advanced zoom and better optic systems” to address these issues. Alemany adds, “The fixtures are catching up, and if you look at a [Martin Professional] MAC 2000 or a Derksen projector or the LSI BP75, these fixtures have stunning optic trains and they can resolve every dot you put into the gobo.”

COMMUNICATION IS EVERYTHING

You've chosen the right fixture. Now you must share this decision with the gobo manufacturer. “We want to know the fixture,” says Hunter. “We want to know the wattage, the application. We like to know as much information beforehand as possible. We have ways to help enhance the gobo so it may not ‘halo’ in a certain fixture; we can move the image around slightly so it won't bleed on the right or the left. We learn about every fixture as they come out. Maybe we need to shrink the image down a little for one fixture, or use smaller letters to avoid that halo effect in another.” Alemany says, “Many times, people don't realize that we need to know the specific fixture to know if we need to flip the image. We need to know if the fixture has a mirror or not and, in moving lights, often you can only load some of these fixtures one way.”

It all comes down to sharing information. The more your gobo manufacturer knows, the better the result. As Alemany says, “You can never tell us more then we want to know. The hardest part for the gobo maker is getting the full information: How is it going to be used? What do you want to see projected?” Hunter adds, “The client needs to think about the final look. We get a logo on a white background but they really want a black background because only one out of 100 people really wants a big circle of light with the logo floating in the middle of it.” A gobo manufacturer can help you with questions you may not even know to ask. “More and more people who are not in the industry are using gobos,” says Hutton. “If you help the client feel more confident, they will have confidence in your product and will come back to you.”

In the end, there are a number of resources for customers; gobo manufacturers are working hard at making the information available on websites and in conversations with clients. If you take the time to really work with manufacturers, they can get you the right results. As Alemany points out, “Ultimately, nobody is buying a gobo — you are buying a projection. The end product is on the wall and not the piece of glass.”

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