<s>
Posterization	B-Algorithm
or	O
posterisation	B-Algorithm
of	O
an	O
image	O
is	O
the	O
conversion	O
of	O
a	O
continuous	O
gradation	O
of	O
tone	O
to	O
several	O
regions	O
of	O
fewer	O
tones	O
,	O
causing	O
abrupt	O
changes	O
from	O
one	O
tone	O
to	O
another	O
.	O
</s>
<s>
It	O
can	O
now	O
be	O
done	O
photographically	O
or	O
with	O
digital	O
image	O
processing	O
,	O
and	O
may	O
be	O
deliberate	O
or	O
an	O
unintended	O
artifact	B-Algorithm
of	O
color	B-Algorithm
quantization	I-Algorithm
.	O
</s>
<s>
Posterization	B-Algorithm
if	O
often	O
the	O
first	O
step	O
in	O
vectorization	O
(	O
tracing	O
)	O
of	O
an	O
image	O
.	O
</s>
<s>
For	O
artistic	O
effect	O
,	O
most	O
image	B-Application
editing	I-Application
programs	I-Application
provide	O
a	O
posterization	B-Algorithm
feature	O
,	O
or	O
photographic	O
processes	O
may	O
be	O
used	O
.	O
</s>
<s>
Unwanted	O
posterization	B-Algorithm
,	O
also	O
known	O
as	O
banding	B-Algorithm
,	O
may	O
occur	O
when	O
the	O
color	O
depth	O
,	O
sometimes	O
called	O
bit	O
depth	O
,	O
is	O
insufficient	O
to	O
accurately	O
sample	O
a	O
continuous	O
gradation	O
of	O
color	O
tone	O
.	O
</s>
<s>
When	O
discussing	O
fixed	B-General_Concept
pixel	I-General_Concept
displays	I-General_Concept
,	O
such	O
as	O
LCD	O
and	O
plasma	O
televisions	O
,	O
this	O
effect	O
is	O
referred	O
to	O
as	O
false	O
contouring	O
.	O
</s>
<s>
Additionally	O
,	O
compression	B-Algorithm
in	O
image	O
formats	O
such	O
as	O
JPEG	O
can	O
also	O
result	O
in	O
posterization	B-Algorithm
when	O
a	O
smooth	O
gradient	O
of	O
colour	O
or	O
luminosity	O
is	O
compressed	O
into	O
discrete	O
quantized	O
blocks	O
with	O
stepped	O
gradients	O
.	O
</s>
<s>
Posterization	B-Algorithm
is	O
a	O
process	O
in	O
photograph	O
development	O
which	O
converts	O
normal	O
photographs	O
into	O
an	O
image	O
consisting	O
of	O
distinct	O
,	O
but	O
flat	O
,	O
areas	O
of	O
different	O
tones	O
or	O
colors	O
.	O
</s>
<s>
Printing	O
posterization	B-Algorithm
from	O
black	O
and	O
white	O
requires	O
density	O
separations	O
,	O
which	O
one	O
then	O
prints	O
on	O
the	O
same	O
piece	O
of	O
paper	O
to	O
create	O
the	O
whole	O
image	O
.	O
</s>
<s>
Typically	O
,	O
posterization	B-Algorithm
is	O
used	O
for	O
tracing	O
contour	O
lines	O
and	O
vectorizing	O
photo-realistic	O
images	O
.	O
</s>
<s>
A	O
visual	O
artist	O
,	O
faced	O
with	O
line	O
art	O
that	O
has	O
been	O
damaged	O
through	O
JPEG	O
compression	B-Algorithm
,	O
may	O
consider	O
posterizing	B-Algorithm
the	O
image	O
as	O
a	O
first	O
step	O
to	O
remove	O
artifacts	B-Algorithm
on	O
the	O
edges	O
of	O
the	O
image	O
.	O
</s>
<s>
Temporal	O
posterization	B-Algorithm
is	O
the	O
visual	O
effect	O
of	O
reducing	O
the	O
number	O
of	O
frames	O
of	O
video	O
,	O
while	O
not	O
reducing	O
the	O
total	O
time	O
it	O
takes	O
the	O
video	O
to	O
play	O
.	O
</s>
<s>
This	O
compares	O
to	O
regular	O
posterization	B-Algorithm
,	O
where	O
the	O
number	O
of	O
individual	O
color	O
variations	O
is	O
reduced	O
,	O
while	O
the	O
overall	O
range	O
of	O
colors	O
is	O
not	O
.	O
</s>
<s>
Unlike	O
a	O
pulldown	B-Application
,	O
the	O
unused	O
frames	O
are	O
simply	O
discarded	O
,	O
and	O
it	O
is	O
intended	O
to	O
be	O
apparent	O
(	O
longer	O
than	O
the	O
persistence	O
of	O
vision	O
that	O
video	O
and	O
motion	O
pictures	O
normally	O
depend	O
on	O
)	O
.	O
</s>
<s>
More	O
formally	O
,	O
this	O
is	O
downsampling	B-Algorithm
in	O
the	O
time	O
dimension	O
,	O
as	O
it	O
is	O
reducing	O
the	O
resolution	O
(	O
precision	O
of	O
the	O
input	O
)	O
,	O
not	O
the	O
bit	O
rate	O
(	O
precision	O
of	O
the	O
output	O
,	O
as	O
in	O
posterization	B-Algorithm
)	O
.	O
</s>
<s>
The	O
resulting	O
stop-go	O
motion	O
is	O
a	O
temporal	O
form	O
of	O
jaggies	B-Algorithm
;	O
formally	O
,	O
a	O
form	O
of	O
aliasing	B-Error_Name
.	O
</s>
<s>
This	O
effect	O
may	O
be	O
the	O
intention	O
,	O
but	O
to	O
reduce	O
the	O
frame	O
rate	O
without	O
introducing	O
this	O
effect	O
,	O
one	O
may	O
use	O
temporal	B-Algorithm
anti-aliasing	I-Algorithm
,	O
which	O
yields	O
motion	O
blur	O
.	O
</s>
