When a large
projection
is required or in instances where projections are called for in combination with strong
stage
lighting, the standard AV
slide
projector, even in its semi professional versions, is not sufficient. The quality of the
image
depends on the
level
of the
stage
lighting and on the reflective qualities of the
projection
surface. On a dark
stage
the
image
will be strong and clear. As more light is added to the stage, the clarity and strength of the
image
may deteriorate.
Therefore when projections are used on a brightly lit stage, a high power scenic
projector
with a 1200W (or higher) discharge
lamp
must be used.
Slides are made of plate glass or another transparent material like celluloid which carries the visual material to be projected. Most projectors use heat shields and forced air cooling systems to protect the
slide
from the excessive heat produced by the light source. Scenic projectors use large slides, 18x18cm or 24x24cm, which collects more light than a small slide, further augmenting the brightness of the projection. The size of the
slide
also makes it possible for the artist to paint the visual material directly on the transparency, ensuring very high fidelity of color and detail. There are various
slide
change mechanisms which enable
remote control
selection of slides. Since the discharge lamps of scenic projectors cannot be dimmed with standard
stage
dimmers, a douser or other means of mechanical dimming is used.
Scenic projectors are also used in advertising and are strong enough to brightly illuminate an entire building.
