<s>
A	O
monochrome	B-Device
monitor	I-Device
is	O
a	O
type	O
of	O
computer	B-Device
monitor	I-Device
in	O
which	O
computer	O
text	O
and	O
images	O
are	O
displayed	O
in	O
varying	O
tones	O
of	O
only	O
one	O
color	O
,	O
as	O
opposed	O
to	O
a	O
color	B-Device
monitor	I-Device
that	O
can	O
display	O
text	O
and	O
images	O
in	O
multiple	O
colors	O
.	O
</s>
<s>
They	O
were	O
very	O
common	O
in	O
the	O
early	O
days	O
of	O
computing	O
,	O
from	O
the	O
1960s	O
through	O
the	O
1980s	O
,	O
before	O
color	B-Device
monitors	I-Device
became	O
widely	O
commercially	O
available	O
.	O
</s>
<s>
Green	O
screen	O
was	O
the	O
common	O
name	O
for	O
a	O
monochrome	B-Device
monitor	I-Device
using	O
a	O
green	O
"	O
P1	O
"	O
phosphor	O
screen	O
;	O
the	O
term	O
is	O
often	O
misused	O
to	O
refer	O
to	O
any	O
block	O
mode	O
display	O
terminal	O
,	O
regardless	O
of	O
color	O
,	O
e.g.	O
,	O
IBM	O
3279	O
,	O
3290	O
.	O
</s>
<s>
Abundant	O
in	O
the	O
early-to-mid-1980s	O
,	O
they	O
succeeded	O
Teletype	O
terminals	B-General_Concept
and	O
preceded	O
color	O
CRTs	O
and	O
later	O
LCDs	B-Device
as	O
the	O
predominant	O
visual	O
output	O
device	O
for	O
computers	O
.	O
</s>
<s>
The	O
most	O
common	O
technology	O
for	O
monochrome	B-Device
monitors	I-Device
was	O
the	O
CRT	B-Device
,	O
although	O
,	O
e.g.	O
,	O
plasma	O
displays	O
,	O
were	O
also	O
used	O
.	O
</s>
<s>
Unlike	O
color	B-Device
monitors	I-Device
,	O
which	O
display	O
text	O
and	O
graphics	O
in	O
multiple	O
colors	O
through	O
the	O
use	O
of	O
alternating-intensity	O
red	O
,	O
green	O
,	O
and	O
blue	O
phosphors	O
,	O
monochrome	B-Device
monitors	I-Device
have	O
only	O
one	O
color	O
of	O
phosphor	O
(	O
mono	O
means	O
"	O
one	O
"	O
,	O
and	O
chrome	O
means	O
"	O
color	O
"	O
)	O
.	O
</s>
<s>
Some	O
monitors	O
have	O
the	O
ability	O
to	O
vary	O
the	O
brightness	O
of	O
individual	O
pixels	B-Algorithm
,	O
thereby	O
creating	O
the	O
illusion	O
of	O
depth	O
and	O
color	O
,	O
exactly	O
like	O
a	O
black-and-white	O
television	O
.	O
</s>
<s>
Typically	O
,	O
only	O
a	O
limited	O
set	O
of	O
brightness	O
levels	O
was	O
provided	O
to	O
save	O
display	B-Algorithm
memory	I-Algorithm
which	O
was	O
very	O
expensive	O
in	O
the	O
'	O
70s	O
and	O
'	O
80s	O
.	O
</s>
<s>
Either	O
normal/bright	O
or	O
normal/dim	O
(	O
1	O
bit	O
)	O
per	O
character	O
as	O
in	O
the	O
VT100	B-Device
or	O
black	O
,	O
dark	O
gray	O
,	O
light	O
gray	O
,	O
white	O
(	O
2bit	O
)	O
per	O
pixel	B-Algorithm
like	O
the	O
NeXT	B-Device
MegaPixel	I-Device
Display	I-Device
.	O
</s>
<s>
Monochrome	B-Device
monitors	I-Device
are	O
commonly	O
available	O
in	O
three	O
colors	O
:	O
if	O
the	O
P1	O
phosphor	O
is	O
used	O
,	O
the	O
screen	O
is	O
green	O
monochrome	O
.	O
</s>
<s>
An	O
amber	B-Device
screen	I-Device
was	O
claimed	O
to	O
give	O
improved	O
ergonomics	O
,	O
specifically	O
by	O
reducing	O
eye	O
strain	O
;	O
this	O
claim	O
appears	O
to	O
have	O
little	O
scientific	O
basis	O
.	O
</s>
<s>
Well-known	O
examples	O
of	O
early	O
monochrome	B-Device
monitors	I-Device
are	O
the	O
VT100	B-Device
from	O
Digital	O
Equipment	O
Corporation	O
,	O
released	O
in	O
1978	O
,	O
the	O
Apple	B-Device
Monitor	I-Device
III	I-Device
in	O
1980	O
,	O
and	O
the	O
IBM	B-Device
5151	I-Device
,	O
which	O
accompanied	O
the	O
IBM	B-Device
PC	I-Device
model	B-Device
5150	I-Device
upon	O
its	O
1981	O
release	O
.	O
</s>
<s>
The	O
5151	O
was	O
designed	O
to	O
work	O
with	O
the	O
PC	O
's	O
Monochrome	B-Device
Display	I-Device
Adapter	I-Device
(	O
MDA	B-Device
)	O
text-only	O
graphics	B-Device
card	I-Device
,	O
but	O
the	O
third-party	O
Hercules	B-Device
Graphics	I-Device
Card	I-Device
became	O
a	O
popular	O
companion	O
to	O
the	O
5151	O
screen	O
because	O
of	O
the	O
Hercules	O
 '	O
comparatively	O
high-resolution	O
bitmapped	O
720×348	O
pixel	B-Algorithm
monochrome	O
graphics	O
capability	O
,	O
much	O
used	O
for	O
business	O
presentation	O
graphics	O
generated	O
from	O
spreadsheets	B-Application
like	O
Lotus	B-Application
1-2-3	I-Application
.	O
</s>
<s>
This	O
was	O
much	O
higher	O
resolution	O
than	O
the	O
alternative	O
IBM	B-Device
Color	I-Device
Graphics	I-Device
Adapter	I-Device
320×200	O
pixel	B-Algorithm
,	O
or	O
640×200	O
pixel	B-Algorithm
graphic	O
standard	O
.	O
</s>
<s>
It	O
could	O
also	O
run	O
most	O
programs	O
written	O
for	O
the	O
CGA	B-Device
card	O
's	O
standard	O
graphics	O
modes	O
.	O
</s>
<s>
Monochrome	B-Device
monitors	I-Device
continued	O
to	O
be	O
used	O
,	O
even	O
after	O
the	O
introduction	O
of	O
higher	O
resolution	O
color	O
IBM	B-Device
Enhanced	I-Device
Graphics	I-Device
Adapter	I-Device
and	O
Video	B-Protocol
Graphics	I-Protocol
Array	I-Protocol
standards	O
in	O
the	O
late	O
1980s	O
,	O
for	O
dual-monitor	B-General_Concept
applications	O
.	O
</s>
<s>
Pixel	B-Algorithm
for	O
pixel	B-Algorithm
,	O
monochrome	B-Device
CRT	I-Device
monitors	I-Device
produce	O
sharper	O
text	O
and	O
images	O
than	O
color	O
CRT	B-Device
monitors	I-Device
.	O
</s>
<s>
This	O
is	O
because	O
a	O
monochrome	B-Device
monitor	I-Device
is	O
made	O
up	O
of	O
a	O
continuous	O
coating	O
of	O
phosphor	O
and	O
the	O
sharpness	O
can	O
be	O
controlled	O
by	O
focusing	O
the	O
electron	O
beam	O
;	O
whereas	O
on	O
a	O
color	B-Device
monitor	I-Device
,	O
screen	O
space	O
is	O
divided	O
into	O
triads	O
of	O
three	O
phosphor	O
dots	O
(	O
one	O
red	O
,	O
one	O
blue	O
,	O
one	O
green	O
)	O
separated	O
by	O
a	O
mask	O
.	O
</s>
<s>
The	O
effective	O
resolution	O
of	O
a	O
color	B-Device
monitor	I-Device
is	O
limited	O
by	O
the	O
density	O
of	O
these	O
triads	O
.	O
</s>
<s>
Furthermore	O
,	O
pixels	B-Algorithm
in	O
the	O
source	O
image	O
will	O
not	O
align	O
precisely	O
to	O
these	O
triads	O
,	O
so	O
moire	O
effects	O
will	O
occur	O
as	O
the	O
image	O
resolution	O
approaches	O
the	O
limit	O
imposed	O
by	O
the	O
size	O
of	O
the	O
phosphor	O
triads	O
.	O
</s>
<s>
Monochrome	B-Device
monitors	I-Device
were	O
used	O
in	O
almost	O
all	O
dumb	O
terminals	B-General_Concept
and	O
were	O
widely	O
used	O
in	O
text-based	O
applications	O
such	O
as	O
computerized	O
cash	O
registers	O
and	O
point	O
of	O
sale	O
systems	O
because	O
of	O
their	O
superior	O
sharpness	O
and	O
enhanced	O
readability	O
.	O
</s>
<s>
Some	O
green	B-Device
screen	I-Device
displays	I-Device
were	O
furnished	O
with	O
a	O
particularly	O
full/intense	O
phosphor	O
coating	O
,	O
making	O
the	O
characters	O
very	O
clear	O
and	O
sharply	O
defined	O
(	O
thus	O
easy	O
to	O
read	O
)	O
but	O
generating	O
an	O
afterglow-effect	O
(	O
sometimes	O
called	O
a	O
"	O
ghost	O
image	O
"	O
)	O
when	O
the	O
text	O
scrolled	O
down	O
the	O
screen	O
or	O
when	O
a	O
screenful	O
of	O
information	O
was	O
quickly	O
replaced	O
with	O
another	O
as	O
in	O
word	B-General_Concept
processing	I-General_Concept
page	O
up/down	O
operations	O
.	O
</s>
<s>
The	O
opening	O
titles	O
of	O
the	O
first	O
Ghost	O
in	O
the	O
Shell	O
film	O
and	O
the	O
Matrix	O
source	O
code	O
of	O
the	O
Matrix	O
trilogy	O
science	O
fiction	O
films	O
prominently	O
feature	O
computer	B-Device
displays	I-Device
with	O
ghosting	O
green	O
text	O
.	O
</s>
<s>
Monochrome	B-Device
monitors	I-Device
are	O
particularly	O
susceptible	O
to	O
screen	B-General_Concept
burn	I-General_Concept
(	O
hence	O
the	O
advent	O
,	O
and	O
name	O
,	O
of	O
the	O
screensaver	B-General_Concept
)	O
,	O
because	O
the	O
phosphors	O
used	O
are	O
of	O
very	O
high	O
intensity	O
.	O
</s>
