GAM Pattern - Manual (Page 2)

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Now the reflector needs to be cleaned. With the lens barrel and lenses removed, open up the fixture to get easy access
to the reflector. It is important to remove the lamp (bulb) from the fixture. This makes it easier and safer to clean the reflec-
tor. When cleaning the reflector, try using compressed air to remove the surface dust. It is the safest method and mini-
mizes the chances of damaging the reflector. However, if the reflector is very dirty, the surface dirt needs to be removed.
There are two ways to achieve this. The first method is to use a soft bristled paint brush. Make sure to use a new, clean,
soft bristled paint brush to clean reflectors. It is imperative not to scratch or leave residue on the reflector. If the brush does
not work use a clean, lint-free, damp cloth. Dampen the cloth with distilled water only to avoid leaving residue.
Once the lenses and the reflector are clean, the light can be reassembled. The last and most important step is to optically
align the lamp. Lamp alignment is the single most important factor in extending pattern life. When an ellipsoidal spotlight
is used to light actors, the lamp is often adjusted to produce a hot center and a feathered edge. When using the same
fixture to project an image, it is preferable to back the lamp out of the reflector until the field of light is even all the way
across, with no ‘hot spot’. With an even field, the heat is distributed over the whole surface of the pattern, rather than
concentrated on one part. In addition, the even field allows for a more uniform focus.
Most ellipsoidals have screws and/or knobs and socket mounting plates to align the lamps. First, center the lamp
filament in the field of light. Then, adjust penetration into the reflector. Consult the fixture’s manufacturer instructions for
more details. It is easiest to align an ellipsoidal when it is down and on a dimmer at a lower intensity. The fixture should
be focused on a flat white surface. Aligning a lamp can be a difficult process, but is worth the time; it will extend the life
of the pattern and improve the quality of the image. If the ellipsoidal has been properly cleaned and aligned, it is ready
to project your image. A little bit of work on the ground will reap great rewards when the image is focused on the stage.
A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
J
J
I
I
Socket
Lamp
Reflector
Gate
Framing Shutters
Pattern Holder - Place Pattern
Focal Point - Rays of reflected light
converge here
Plano Convex Lenses
Lens Focusing Knob
Color Frame Holder
ELLIPSOIDAL SPOTLIGHT