<s>
A	O
photolith	B-Application
film	I-Application
is	O
a	O
transparent	O
film	O
,	O
made	O
with	O
some	O
sort	O
of	O
transparent	O
plastic	O
(	O
formerly	O
made	O
of	O
acetate	O
)	O
.	O
</s>
<s>
Nowadays	O
,	O
with	O
the	O
use	O
of	O
laser	O
printers	O
and	O
computers	O
,	O
the	O
photolith	B-Application
film	I-Application
can	O
be	O
based	O
on	O
polyester	O
,	O
vegetable	O
paper	O
or	O
laser	O
film	O
paper	O
.	O
</s>
<s>
It	O
is	O
mainly	O
used	O
in	O
all	O
photolithography	B-Algorithm
processes	O
.	O
</s>
<s>
A	O
color	O
image	O
,	O
or	O
polychromatic	O
,	O
is	O
divided	O
into	O
four	O
basic	O
colors	O
:	O
cyan	O
,	O
the	O
magenta	B-Algorithm
,	O
the	O
yellow	O
and	O
black	O
(	O
the	O
so-called	O
system	O
CMYK	O
(	O
short	O
name	O
from	O
cyan	O
,	O
magenta	B-Algorithm
,	O
yellow	O
and	O
black	O
)	O
,	O
generating	O
four	O
photolith	B-Application
film	I-Application
images	O
,	O
a	O
photo	O
filtered	O
with	O
each	O
of	O
the	O
three	O
basic	O
colors	O
plus	O
a	O
B&W	O
film	O
(	O
addition	O
of	O
the	O
three	O
)	O
.	O
</s>
<s>
For	O
black-and-white	O
images	O
,	O
such	O
as	O
text	O
or	O
simple	O
logos	O
,	O
only	O
one	O
photolith	B-Application
film	I-Application
is	O
needed	O
.	O
</s>
<s>
The	O
photolith	B-Application
film	I-Application
it	O
is	O
sometimes	O
recorded	O
by	O
an	O
optical	O
laser	O
process	O
on	O
an	O
imagesetter	O
machine	O
,	O
coming	O
from	O
a	O
digital	O
file	O
,	O
or	O
by	O
a	O
photographic	O
process	O
in	O
a	O
contact	B-Application
copier	I-Application
,	O
if	O
a	O
physical	O
copy	O
of	O
the	O
original	O
already	O
exist	O
.	O
</s>
<s>
In	O
the	O
old	O
offset	O
printing	O
plates	O
acquire	O
text	O
or	O
images	O
to	O
be	O
printed	O
after	O
being	O
sensitized	O
from	O
a	O
photolith	B-Application
film	I-Application
.	O
</s>
<s>
The	O
photolith	B-Application
films	I-Application
,	O
as	O
well	O
as	O
vegetable	O
and	O
the	O
laser	O
films	O
,	O
are	O
used	O
to	O
store	O
plates	O
,	O
screens	O
or	O
other	O
media	O
sensitive	O
to	O
light	O
as	O
a	O
backup	O
for	O
repeating	O
their	O
processes	O
in	O
the	O
future	O
.	O
</s>
<s>
They	O
normally	O
store	O
the	O
information	O
of	O
the	O
three	O
or	O
four	O
separated	O
colours	O
on	O
monochrome	O
photolith	B-Application
films	I-Application
.	O
</s>
