January 3, 2012
Probability is high that you’ll be
asked to install a front projection
system with 3D capabilities soon if
you haven’t already. Between massive
advertising being pummeled into the
collective conscious of consumers to
manufacturers racing to ensure that
their products are competitive in the
features column, 3D is making its way
into projectors at lower and lower
price points and making consumers
feel they must have this capability to
continue enjoying life. There’s more to
designing one of these systems than just throwing
up a 3D projector, hanging a screen, handing
out some glasses, and dazzling your client into
another dimension.

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A rendering of Stewart’s Silver 5D screen in action
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Active or Passive? If you’ve viewed much 3D
programming, you’ve probably developed a
preference toward one method over the other.
George Walter, Digital Projection’s VP of
Home Cinema, commented, “End users prefer
watching 3D in a passive environment. The
glasses are lighter, they pass more light (allowing
a more social experience with other viewers),
and they are generally more comfortable.”
Proper Screen Selection. Passive 3D systems
require using a silver polarization retention
screen. These materials, however, can
compromise 2D viewing. And since the vast
majority of content is 2D, you wouldn’t want to
compromise that. Walter suggested, “The best
solution would be to have two screens; one silver,
dedicated for 3D, and one selected for optimal
2D viewing.” Barring a two-screen approach,
some manufacturers have developed materials
meant to produce the fewest image compromises
for both 2D and 3D viewing. One advantage of
active systems is that any screen material will do,
though a higher gain model will help offset some
of the light lost through the 3D filtering process.
Bigger is Better. A huge reason why people opt
for projection in the first place is for a larger,
more immersive experience. This plays right
into 3D’s strengths. “The 3D viewing experience
gets better and is much more involving as you get
larger and approach image sizes that fill up your
peripheral vision,” Walter said.
Screen Innovations director of sales, Blake
Vackar concurred, saying, “It is best to view 3D
content on a screen that is 100 inches or larger.”
The only drawback to the large screen size is
that it requires more projector light horsepower
to drive.
Seating Considerations. As viewers start
sitting off-center, chances of image artifacts
are substantially increased, especially as you
use higher gain screens. “The more offset the
viewer is, the greater
the possibility of
getting 3D shadows in
the image or ‘double
vision,’ neither of
which is enjoyable,”
Vackar explained.
And, for the best
3D image you’ll likely
need a high-gain
screen. “3D screens
tend to have elevated
gain for recovery of
filter insertion losses,”
Stewart Filmscreen’s
president, Grant Stewart said, “so they are
more directional than reference home theater
screens.” This means that viewers should be
clustered in seats near the middle of the room.
Stewart suggests following SMPTE guidelines
for seating distances, “In general between 3 and
3.3 times the image height is a very workable
figure for home cinema 2D or 3D,” he said.
Other Considerations. Beyond obvious home
theater design elements, like keeping proper
sightlines and making sure that there is adequate
coverage for all viewers glasses to be in range
of receiving the sync signals in active systems,
Walter stressed eliminating anything that can
create a distraction. “The whole 3D experience
involves trying to trick your brain,” he said.
“You need to relax enough for your brain to say,
‘I’m being tricked, and it’s OK.’ Anything in the
environment that distracts the viewer is going to
be a detriment to the 3D experience.”
John Sciacca is a principal with Custom
Theater and Audio, in Myrtle Beach, SC.
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