<s>
A	O
movie	B-Application
projector	I-Application
is	O
an	O
opto-mechanical	O
device	O
for	O
displaying	O
motion	O
picture	O
film	O
by	O
projecting	O
it	O
onto	O
a	O
screen	O
.	O
</s>
<s>
Most	O
of	O
the	O
optical	O
and	O
mechanical	O
elements	O
,	O
except	O
for	O
the	O
illumination	O
and	O
sound	O
devices	O
,	O
are	O
present	O
in	O
movie	B-Application
cameras	I-Application
.	O
</s>
<s>
Modern	O
movie	B-Application
projectors	I-Application
are	O
specially	O
built	O
video	B-Device
projectors	I-Device
.	O
</s>
<s>
Many	O
projectors	O
are	O
specific	O
to	O
a	O
particular	O
film	O
gauge	O
and	O
not	O
all	O
movie	B-Application
projectors	I-Application
are	O
film	B-Application
projectors	I-Application
since	O
the	O
use	O
of	O
film	O
is	O
required	O
.	O
</s>
<s>
The	O
main	O
precursor	O
to	O
the	O
movie	B-Application
projector	I-Application
was	O
the	O
magic	B-Device
lantern	I-Device
.	O
</s>
<s>
Magic	B-Device
lantern	I-Device
presentations	O
may	O
often	O
have	O
had	O
relatively	O
small	O
audiences	O
,	O
but	O
the	O
very	O
popular	O
phantasmagoria	B-Application
and	O
dissolving	O
views	O
shows	O
were	O
usually	O
performed	O
in	O
proper	O
theatres	O
,	O
large	O
tents	O
or	O
especially	O
converted	O
spaces	O
with	O
plenty	O
seats	O
.	O
</s>
<s>
Wordsworth	O
Donisthorpe	O
patented	O
ideas	O
for	O
a	O
cinematographic	O
film	B-Application
camera	I-Application
and	O
a	O
film	O
presentation	O
system	O
in	O
1876	O
.	O
</s>
<s>
In	O
reply	O
to	O
the	O
introduction	O
of	O
the	O
phonograph	O
and	O
a	O
magazine	O
's	O
suggestion	O
that	O
it	O
could	O
be	O
combined	O
with	O
projection	O
of	O
stereoscopic	B-Algorithm
photography	I-Algorithm
,	O
Donisthorpe	O
stated	O
that	O
he	O
could	O
do	O
even	O
better	O
and	O
announce	O
that	O
he	O
would	O
present	O
such	O
images	O
in	O
motion	O
.	O
</s>
<s>
In	O
1886	O
Louis	O
Le	O
Prince	O
applied	O
for	O
a	O
US	O
patent	O
for	O
a	O
16-lens	O
device	O
that	O
combined	O
a	O
motion	B-Application
picture	I-Application
camera	I-Application
with	O
a	O
projector	O
.	O
</s>
<s>
Hand-cranked	O
tinplate	O
toy	O
movie	B-Application
projectors	I-Application
,	O
also	O
called	O
vintage	O
projectors	O
,	O
were	O
used	O
taking	O
standard	O
35	O
mm	O
8	O
perforation	O
silent	O
cinema	O
films	O
.	O
</s>
<s>
In	O
1999	O
,	O
digital	O
cinema	B-Application
projectors	I-Application
were	O
being	O
tried	O
out	O
in	O
some	O
movie	O
theatres	O
.	O
</s>
<s>
Due	O
to	O
their	O
relatively	O
low	O
resolution	O
(	O
usually	O
only	O
2K	B-General_Concept
)	O
compared	O
to	O
later	O
digital	O
cinema	O
systems	O
,	O
the	O
images	O
at	O
the	O
time	O
had	O
visible	O
pixels	O
.	O
</s>
<s>
By	O
2006	O
,	O
the	O
advent	O
of	O
much	O
higher	O
4K	B-Architecture
resolution	I-Architecture
digital	O
projection	O
reduced	O
pixel	O
visibility	O
.	O
</s>
<s>
By	O
2009	O
,	O
movie	O
theatres	O
started	O
replacing	O
film	B-Application
projectors	I-Application
with	O
digital	B-Device
projectors	I-Device
.	O
</s>
<s>
Although	O
usually	O
more	O
expensive	O
than	O
film	B-Application
projectors	I-Application
,	O
high-resolution	O
digital	B-Device
projectors	I-Device
offer	O
many	O
advantages	O
over	O
traditional	O
film	O
units	O
.	O
</s>
<s>
For	O
example	O
,	O
digital	B-Device
projectors	I-Device
contain	O
no	O
moving	O
parts	O
except	O
fans	O
,	O
can	O
be	O
operated	O
remotely	O
,	O
are	O
relatively	O
compact	O
and	O
have	O
no	O
film	O
to	O
break	O
,	O
scratch	O
or	O
change	O
reels	O
of	O
.	O
</s>
<s>
This	O
will	O
not	O
work	O
with	O
(	O
now	O
obsolete	O
)	O
cathode	B-Device
ray	I-Device
tube	I-Device
displays	I-Device
,	O
due	O
to	O
the	O
persistence	O
of	O
the	O
phosphors	O
,	O
nor	O
with	O
LCD	B-Device
or	O
DLP	B-General_Concept
light	O
projectors	O
,	O
because	O
they	O
refresh	O
the	O
image	O
instantly	O
with	O
no	O
blackout	O
intervals	O
as	O
with	O
traditional	O
film	B-Application
projectors	I-Application
.	O
</s>
<s>
When	O
the	O
electric	O
motor	O
supplanted	O
hand	O
cranking	O
in	O
both	O
movie	B-Application
cameras	I-Application
and	O
projectors	O
,	O
a	O
more	O
uniform	O
frame	O
rate	O
became	O
possible	O
.	O
</s>
<s>
Virtually	O
all	O
film	B-Application
projectors	I-Application
in	O
commercial	O
movie	O
theaters	O
project	O
at	O
a	O
constant	O
speed	O
of	O
24	O
frame/s	O
.	O
</s>
<s>
The	B-Application
Hobbit	I-Application
was	O
shot	O
at	O
48	O
frames/sec	O
and	O
projected	O
at	O
the	O
higher	O
frame	O
rate	O
at	O
specially	O
equipped	O
theaters	O
.	O
</s>
<s>
As	O
in	O
a	O
slide	B-Device
projector	I-Device
there	O
are	O
essential	O
optical	O
elements	O
:	O
</s>
<s>
Incandescent	O
lighting	O
and	O
even	O
limelight	O
were	O
the	O
first	O
light	O
sources	O
used	O
in	O
film	B-Application
projection	I-Application
.	O
</s>
<s>
Projector	O
lenses	O
differ	O
in	O
aperture	B-General_Concept
and	O
focal	B-Algorithm
length	I-Algorithm
to	O
suit	O
different	O
needs	O
.	O
</s>
<s>
One	O
way	O
that	O
aspect	O
ratios	O
are	O
set	O
is	O
with	O
the	O
appropriate	O
aperture	B-General_Concept
plate	O
,	O
a	O
piece	O
of	O
metal	O
with	O
a	O
precisely	O
cut	O
rectangular	O
hole	O
in	O
the	O
middle	O
of	O
equivalent	O
aspect	O
ratio	O
.	O
</s>
<s>
The	O
aperture	B-General_Concept
plate	O
is	O
placed	O
just	O
behind	O
the	O
gate	O
,	O
and	O
masks	O
off	O
any	O
light	O
from	O
hitting	O
the	O
image	O
outside	O
of	O
the	O
area	O
intended	O
to	O
be	O
shown	O
.	O
</s>
<s>
Using	O
an	O
aperture	B-General_Concept
plate	O
to	O
accomplish	O
a	O
wider	O
aspect	O
ratio	O
is	O
inherently	O
wasteful	O
of	O
film	O
,	O
as	O
a	O
portion	O
of	O
the	O
standard	O
frame	O
is	O
unused	O
.	O
</s>
<s>
The	O
anamorphic	O
format	O
uses	O
special	O
optics	B-Algorithm
to	O
squeeze	O
a	O
high	O
aspect	O
ratio	O
image	O
onto	O
a	O
standard	O
Academy	O
frame	O
thus	O
eliminating	O
the	O
need	O
to	O
change	O
the	O
costly	O
precision	O
moving	O
parts	O
of	O
the	O
intermittent	O
mechanisms	O
.	O
</s>
<s>
In	O
the	O
early	O
years	O
,	O
with	O
no	O
automation	B-Application
,	O
errors	O
were	O
far	O
from	O
unknown	O
:	O
these	O
included	O
starting	O
a	O
movie	O
that	O
had	O
not	O
been	O
rewound	O
,	O
and	O
getting	O
reels	O
confused	O
,	O
so	O
they	O
were	O
projected	O
in	O
the	O
wrong	O
order	O
.	O
</s>
<s>
The	O
single	O
reel	O
system	O
can	O
allow	O
for	O
the	O
complete	O
automation	B-Application
of	O
the	O
projection	O
booth	O
operations	O
,	O
given	O
the	O
proper	O
auxiliary	O
equipment	O
.	O
</s>
<s>
It	O
is	O
the	O
complete	O
automation	B-Application
of	O
projection	O
that	O
has	O
enabled	O
the	O
modern	O
"	O
multiplex	O
"	O
cinema	O
–	O
a	O
single	O
site	O
typically	O
containing	O
from	O
8	O
to	O
24	O
theaters	O
with	O
only	O
a	O
few	O
projection	O
and	O
sound	O
technicians	O
,	O
rather	O
than	O
a	O
platoon	O
of	O
projectionists	O
.	O
</s>
<s>
As	O
with	O
motion	B-Application
picture	I-Application
cameras	I-Application
,	O
the	O
intermittent	O
motion	O
of	O
the	O
gate	O
requires	O
that	O
there	O
be	O
loops	O
above	O
and	O
below	O
the	O
gate	O
in	O
order	O
to	O
serve	O
as	O
a	O
buffer	O
between	O
the	O
constant	O
speed	O
enforced	O
by	O
the	O
sprockets	O
above	O
and	O
below	O
the	O
gate	O
and	O
the	O
intermittent	O
motion	O
enforced	O
at	O
the	O
gate	O
.	O
</s>
<s>
This	O
is	O
similar	O
to	O
the	O
claw	O
mechanism	O
in	O
a	O
motion	B-Application
picture	I-Application
camera	I-Application
.	O
</s>
<s>
Optical	O
sound	O
constitutes	O
the	O
recording	O
and	O
reading	O
of	O
amplitude	B-Application
based	O
on	O
the	O
amount	O
of	O
light	O
that	O
is	O
projected	O
through	O
a	O
soundtrack	O
area	O
on	O
a	O
film	O
using	O
an	O
illuminating	O
light	O
or	O
laser	O
and	O
a	O
photocell	O
or	O
photodiode	O
.	O
</s>
<s>
The	O
space	O
between	O
solid	O
points	O
represented	O
amplitude	B-Application
and	O
was	O
picked	O
up	O
by	O
the	O
photo-electric	O
cell	O
on	O
the	O
other	O
side	O
of	O
a	O
steady	O
,	O
thin	O
beam	O
of	O
light	O
being	O
shined	O
through	O
it	O
.	O
</s>
<s>
The	O
alternative	O
and	O
ultimately	O
the	O
successor	O
of	O
variable	O
density	O
has	O
been	O
the	O
variable	O
area	O
track	O
,	O
in	O
which	O
a	O
clear	O
,	O
vertical	O
waveform	O
against	O
black	O
represents	O
the	O
sound	O
,	O
and	O
the	O
width	O
of	O
the	O
waveform	O
is	O
equivalent	O
to	O
the	O
amplitude	B-Application
.	O
</s>
<s>
The	O
first	O
form	O
of	O
magnetic	O
sound	O
was	O
the	O
double-head	O
system	O
,	O
in	O
which	O
the	O
movie	B-Application
projector	I-Application
was	O
interlocked	O
with	O
a	O
dubber	O
playing	O
a	O
35mm	O
reel	O
of	O
a	O
full-coat	O
,	O
or	O
film	O
completely	O
coated	O
with	O
magnetic	O
iron-oxide	O
.	O
</s>
<s>
SDDS	O
premiered	O
with	O
the	O
film	O
Last	B-Application
Action	I-Application
Hero	I-Application
.	O
</s>
<s>
The	O
images	O
between	O
each	O
perforation	O
are	O
read	O
by	O
a	O
CCD	B-Algorithm
located	O
either	O
above	O
the	O
projector	O
or	O
in	O
the	O
regular	O
analog	O
sound	O
head	O
below	O
the	O
film	O
gate	O
,	O
a	O
digital	O
delay	O
within	O
the	O
processor	O
allowing	O
correct	O
lip-sync	O
to	O
be	O
achieved	O
regardless	O
of	O
the	O
position	O
of	O
the	O
reader	O
relative	O
to	O
the	O
picture	O
gate	O
.	O
</s>
<s>
Dolby	O
Digital	O
officially	O
premiered	O
with	O
the	O
film	O
Batman	B-Application
Returns	I-Application
,	O
but	O
it	O
was	O
earlier	O
tested	O
at	O
some	O
screenings	O
of	O
Star	O
Trek	O
VI	O
:	O
The	O
Undiscovered	O
Country	O
.	O
</s>
<s>
For	O
techniques	O
used	O
to	O
display	O
pictures	O
with	O
a	O
three-dimensional	O
appearance	O
(	O
3D	O
)	O
,	O
see	O
the	O
3-D	B-Algorithm
film	I-Algorithm
article	O
for	O
some	O
movie	O
history	O
and	O
the	O
stereoscopy	B-Algorithm
article	O
for	O
technical	O
information	O
.	O
</s>
