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GOBO is a lighting
term for a metal or glass template that can be inserted into a
focusing fixture to project an image.
The term GOBO
literally means, "GOes Before Optics". And, while the
history of GOBOs beyond that is fairly insignificant, what is
important is whether or not you can or should use one.
Does my fixture focus?
The first question
you need to ask is whether you have a focusing fixture. In a typical
theatrical application, focusing fixtures are known as ellipsoidal
reflector spotlights. Brand names for these fixtures include: Leko,
Source Four, Shakespeare, 360Q, ERS, MiniEllips, MicroEllips, . These
fixtures are designed to have a "gate" which accepts a
pattern holder. It can be found on the top of the fixture just
forward of the shutters. If your fixture does not have a gate, most
likely you cannot use a GOBO.
Fixtures that
cannot accommodate a GOBO: fresnels, par cans, scoops, cyc lights,
follow spots, beam projectors, and borderlights.
Why Do I need a GOBO?
Some lighting
designers use GOBOS to project literal images. You will see GOBOS for
leaf patterns, window patterns, doorways, graphics (hearts, stars,
triangles), and foliage. These images are typically used with a sharp
focus to show clearly what the image is.
You can also use
GOBOS known as "breakups" for texturing an area. These
GOBOS include bubbles, circles, dots, holes, lines, woven patterns,
geometric shapes, and foliage. These images are typically used with a
soft-edge focus to blur or distort the image.
In retail
applications, GOBOS can be used to project literal images, textures,
or logos. Many retail stores use a combination of GOBOS and
"moving fixtures" to make a store’s logo move from
outside of the store to just inside the door. Conversely, a logo may
be stationary and use a simpler, less expensive theatrical style fixture.
So, why do I need
a GOBO? Well, let’s say for example that you are lighting a show
that has several different locations, both indoors and outdoors, and
that the director and set designer have opted for a minimalist set.
Your challenge as lighting designer is to convey the different
locations with light. In addition to the choice of colors, you would
be well advised to use GOBOS. You can create a forest (using trees or
leaves), a wide open field (using cloud gobos projected onto a
cyclorama), a library (using windows), a city street scene (using
skylines), a journey into Dante’s Inferno (using flames, and
some breakups), and end with a desert island (using palm trees, palm
leaves and bamboo). You have moved your actors through all of these
locations with the use of color and images, some focused, some not.
But, I have a
retail store, why do I need GOBOS?
That’s a good
question. Our extensive market research has shown the following
characteristics of retail establishments that incorporate image
projection: they are perceived as more cutting edge, they attract
more traffic, and they succeed!
Can I use image
projection for a movie theater? Yes, several movie theaters now use
GOBOS to project the theater chain’s logo in front of the
facility and use GOBOS above the snack bar to advertise vendors.
Guess what? They also CHARGE those vendors for advertising! Your use
of GOBOS has just increased your revenue!
Can I use image
projection for a car lot? Of course! Advertise year-end sales,
special promotions, even projecting an image of salesman of the month!
Any retail
establishment, and some that are not thought of as retail, can
benefit from additional signage. Especially when that signage is
inexpensive, moves, and causes a reaction from prospects.
What type of
GOBO do I need?
That depends on
your application.
If you are working
in a theater and trying to project a tree, you can pretty well assume
that one of the GOBO manufacturers has something that will fit the
bill. Rosco, Apollo, and Great American Market publish catalogs of
standard GOBOS. For the most part, these are metal GOBOS.
If you are working
in a retail environment and need a corporate logo, Coca-Cola
let’s say, you need to order a custom GOBO. Typically, there is
a "set-up" or "tooling" fee (a charge for artwork
preparation), and then a charge for the GOBOS themselves. This can be
inexpensive (no color, just text, cut on metal) or relatively
expensive (many colors and etched onto glass). A good lighting dealer
can offer you guidance here.
If you know that
the fixture you are using handles heat pretty well, and you need to
have color behind your image, you should definitely examine glass as
an option.
If you know that
the fixture burns really hot, and the image is just text, go for the
metal, and order spares!
What About
Intelligent Fixtures?
The manufacturers
of intelligent fixtures have not been kind to those that make GOBOS.
There used to be two sizes of GOBOS "A", and "B".
These options still exist, but there are now 21 sizes listed in
Rosco’s latest Pattern Catalog. Each moving light manufacturer
uses a different size (sometimes from model to model), and you need
to be sure of two things before ordering a GOBO for your moving fixture:
Does my moving
fixture allow me to remove the existing GOBOS and change them? Most
of the manufacturers allow you to do this, but there are still
fixtures on the market that do not allow for GOBO changes. Pop open
your fixture and check it out.
What model fixture
do I have? Knowing that you have a Cyberlight is fine, but you should
know that Cyberlights are available in CX models (which only take
metal GOBOS), and SV versions (which can take metal or glass gobos).
If you have questions, you should contact a qualified lighting dealer.
Are There
Limits to What Kind of Image I Can Project?
With some
limitations, you can project virtually any image. There are
intelligent fixtures that will allow you to take a photograph and
have it etched on glass for projection. The only real limitation is
your imagination.
How Do I
Determine The Size of My Gobo?
The manufacturers
of Gobos have provided us with a chart that compares sizes and
fixtures. For your convenience, you can cross-reference your fixture here.
John Mitchell
Sterling Technical Services
www.LightTrader.com
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