<s>
A	O
color	B-Algorithm
space	I-Algorithm
is	O
a	O
specific	O
organization	O
of	O
colors	O
.	O
</s>
<s>
In	O
combination	O
with	O
color	O
profiling	O
supported	O
by	O
various	O
physical	O
devices	O
,	O
it	O
supports	O
reproducible	O
representations	O
of	O
colorwhether	O
such	O
representation	O
entails	O
an	O
analog	O
or	O
a	O
digital	B-General_Concept
representation	O
.	O
</s>
<s>
A	O
color	B-Algorithm
space	I-Algorithm
may	O
be	O
arbitrary	O
,	O
i.e.	O
</s>
<s>
with	O
physically	O
realized	O
colors	O
assigned	O
to	O
a	O
set	O
of	O
physical	O
color	B-Data_Structure
swatches	I-Data_Structure
with	O
corresponding	O
assigned	O
color	O
names	O
(	O
including	O
discrete	O
numbers	O
infor	O
examplethe	O
Pantone	O
collection	O
)	O
,	O
or	O
structured	O
with	O
mathematical	O
rigor	O
(	O
as	O
with	O
the	O
NCS	O
System	O
,	O
Adobe	O
RGB	O
and	O
sRGB	O
)	O
.	O
</s>
<s>
A	O
"	O
color	B-Algorithm
space	I-Algorithm
"	O
is	O
a	O
useful	O
conceptual	O
tool	O
for	O
understanding	O
the	O
color	O
capabilities	O
of	O
a	O
particular	O
device	O
or	O
digital	B-General_Concept
file	O
.	O
</s>
<s>
When	O
trying	O
to	O
reproduce	O
color	O
on	O
another	O
device	O
,	O
color	B-Algorithm
spaces	I-Algorithm
can	O
show	O
whether	O
shadow/highlight	O
detail	O
and	O
color	O
saturation	O
can	O
be	O
retained	O
,	O
and	O
by	O
how	O
much	O
either	O
will	O
be	O
compromised	O
.	O
</s>
<s>
A	O
"	O
color	O
model	O
"	O
is	O
an	O
abstract	O
mathematical	O
model	O
describing	O
the	O
way	O
colors	O
can	O
be	O
represented	O
as	O
tuples	B-Application
of	O
numbers	O
(	O
e.g.	O
</s>
<s>
triples	O
in	O
RGB	O
or	O
quadruples	O
in	O
CMYK	O
)	O
;	O
however	O
,	O
a	O
color	O
model	O
with	O
no	O
associated	O
mapping	O
function	O
to	O
an	O
absolute	O
color	B-Algorithm
space	I-Algorithm
is	O
a	O
more	O
or	O
less	O
arbitrary	O
color	O
system	O
with	O
no	O
connection	O
to	O
any	O
globally	O
understood	O
system	O
of	O
color	O
interpretation	O
.	O
</s>
<s>
Adding	O
a	O
specific	O
mapping	O
function	O
between	O
a	O
color	O
model	O
and	O
a	O
reference	O
color	B-Algorithm
space	I-Algorithm
establishes	O
within	O
the	O
reference	O
color	B-Algorithm
space	I-Algorithm
a	O
definite	O
"	O
footprint	O
"	O
,	O
known	O
as	O
a	O
gamut	O
,	O
and	O
for	O
a	O
given	O
color	O
model	O
,	O
this	O
defines	O
a	O
color	B-Algorithm
space	I-Algorithm
.	O
</s>
<s>
For	O
example	O
,	O
Adobe	O
RGB	O
and	O
sRGB	O
are	O
two	O
different	O
absolute	O
color	B-Algorithm
spaces	I-Algorithm
,	O
both	O
based	O
on	O
the	O
RGB	O
color	O
model	O
.	O
</s>
<s>
When	O
defining	O
a	O
color	B-Algorithm
space	I-Algorithm
,	O
the	O
usual	O
reference	O
standard	O
is	O
the	O
CIELAB	O
or	O
CIEXYZ	O
color	B-Algorithm
spaces	I-Algorithm
,	O
which	O
were	O
specifically	O
designed	O
to	O
encompass	O
all	O
colors	O
the	O
average	O
human	O
can	O
see	O
.	O
</s>
<s>
Since	O
"	O
color	B-Algorithm
space	I-Algorithm
"	O
identifies	O
a	O
particular	O
combination	O
of	O
the	O
color	O
model	O
and	O
the	O
mapping	O
function	O
,	O
the	O
word	O
is	O
often	O
used	O
informally	O
to	O
identify	O
a	O
color	O
model	O
.	O
</s>
<s>
However	O
,	O
even	O
though	O
identifying	O
a	O
color	B-Algorithm
space	I-Algorithm
automatically	O
identifies	O
the	O
associated	O
color	O
model	O
,	O
this	O
usage	O
is	O
incorrect	O
in	O
a	O
strict	O
sense	O
.	O
</s>
<s>
For	O
example	O
,	O
although	O
several	O
specific	O
color	B-Algorithm
spaces	I-Algorithm
are	O
based	O
on	O
the	O
RGB	O
color	O
model	O
,	O
there	O
is	O
no	O
such	O
thing	O
as	O
the	O
singular	O
RGB	O
color	B-Algorithm
space	I-Algorithm
.	O
</s>
<s>
But	O
it	O
's	O
not	O
clear	O
that	O
they	O
thought	O
of	O
colors	O
as	O
being	O
points	O
in	O
color	B-Algorithm
space	I-Algorithm
.	O
</s>
<s>
The	O
color-space	B-Algorithm
concept	O
was	O
likely	O
due	O
to	O
Hermann	O
Grassmann	O
,	O
who	O
developed	O
it	O
in	O
two	O
stages	O
.	O
</s>
<s>
Colors	O
can	O
be	O
created	O
in	O
printing	O
with	O
color	B-Algorithm
spaces	I-Algorithm
based	O
on	O
the	O
CMYK	O
color	O
model	O
,	O
using	O
the	O
subtractive	O
primary	O
colors	O
of	O
pigment	O
(	O
cyan	O
,	O
magenta	B-Algorithm
,	O
yellow	O
,	O
and	O
black	O
)	O
.	O
</s>
<s>
To	O
create	O
a	O
three-dimensional	O
representation	O
of	O
a	O
given	O
color	B-Algorithm
space	I-Algorithm
,	O
we	O
can	O
assign	O
the	O
amount	O
of	O
magenta	B-Algorithm
color	O
to	O
the	O
representation	O
's	O
X	O
axis	O
,	O
the	O
amount	O
of	O
cyan	O
to	O
its	O
Y	O
axis	O
,	O
and	O
the	O
amount	O
of	O
yellow	O
to	O
its	O
Z	O
axis	O
.	O
</s>
<s>
Colors	O
can	O
be	O
created	O
on	O
computer	B-Device
monitors	I-Device
with	O
color	B-Algorithm
spaces	I-Algorithm
based	O
on	O
the	O
RGB	O
color	O
model	O
,	O
using	O
the	O
additive	O
primary	O
colors	O
(	O
red	O
,	O
green	O
,	O
and	O
blue	O
)	O
.	O
</s>
<s>
Note	O
that	O
colors	O
generated	O
on	O
a	O
given	O
monitor	O
will	O
be	O
limited	O
by	O
the	O
reproduction	O
medium	O
,	O
such	O
as	O
the	O
phosphor	O
(	O
in	O
a	O
CRT	B-Device
monitor	I-Device
)	O
or	O
filters	O
and	O
backlight	O
(	O
LCD	B-Device
monitor	O
)	O
.	O
</s>
<s>
Another	O
way	O
of	O
creating	O
colors	O
on	O
a	O
monitor	O
is	O
with	O
an	O
HSL	O
or	O
HSV	O
color	O
model	O
,	O
based	O
on	O
hue	B-Language
,	O
saturation	O
,	O
brightness	O
(	O
value/brightness	O
)	O
.	O
</s>
<s>
Many	O
color	B-Algorithm
spaces	I-Algorithm
can	O
be	O
represented	O
as	O
three-dimensional	O
values	O
in	O
this	O
manner	O
,	O
but	O
some	O
have	O
more	O
,	O
or	O
fewer	O
dimensions	O
,	O
and	O
some	O
,	O
such	O
as	O
Pantone	O
,	O
cannot	O
be	O
represented	O
in	O
this	O
way	O
at	O
all	O
.	O
</s>
<s>
Color	B-Algorithm
space	I-Algorithm
conversion	I-Algorithm
is	O
the	O
translation	O
of	O
the	O
representation	O
of	O
a	O
color	O
from	O
one	O
basis	O
to	O
another	O
.	O
</s>
<s>
This	O
typically	O
occurs	O
in	O
the	O
context	O
of	O
converting	O
an	O
image	O
that	O
is	O
represented	O
in	O
one	O
color	B-Algorithm
space	I-Algorithm
to	O
another	O
color	B-Algorithm
space	I-Algorithm
,	O
the	O
goal	O
being	O
to	O
make	O
the	O
translated	O
image	O
look	O
as	O
similar	O
as	O
possible	O
to	O
the	O
original	O
.	O
</s>
<s>
The	O
most	O
common	O
incarnation	O
in	O
general	O
use	O
is	O
the	O
24-bit	O
implementation	O
,	O
with	O
8	O
bits	O
,	O
or	O
256	O
discrete	O
levels	O
of	O
color	O
per	O
channel	B-Algorithm
.	O
</s>
<s>
Any	O
color	B-Algorithm
space	I-Algorithm
based	O
on	O
such	O
a	O
24-bit	O
RGB	O
model	O
is	O
thus	O
limited	O
to	O
a	O
range	O
of	O
256×256×256	O
≈	O
16.7	O
million	O
colors	O
.	O
</s>
<s>
This	O
is	O
especially	O
important	O
when	O
working	O
with	O
wide-gamut	O
color	B-Algorithm
spaces	I-Algorithm
(	O
where	O
most	O
of	O
the	O
more	O
common	O
colors	O
are	O
located	O
relatively	O
close	O
together	O
)	O
,	O
or	O
when	O
a	O
large	O
number	O
of	O
digital	B-General_Concept
filtering	O
algorithms	O
are	O
used	O
consecutively	O
.	O
</s>
<s>
The	O
same	O
principle	O
applies	O
for	O
any	O
color	B-Algorithm
space	I-Algorithm
based	O
on	O
the	O
same	O
color	O
model	O
,	O
but	O
implemented	O
at	O
different	O
bit	O
depths	O
.	O
</s>
<s>
CIE	O
1931	O
XYZ	O
color	B-Algorithm
space	I-Algorithm
was	O
one	O
of	O
the	O
first	O
attempts	O
to	O
produce	O
a	O
color	B-Algorithm
space	I-Algorithm
based	O
on	O
measurements	O
of	O
human	O
color	O
perception	O
(	O
earlier	O
efforts	O
were	O
by	O
James	O
Clerk	O
Maxwell	O
,	O
König	O
&	O
Dieterici	O
,	O
and	O
Abney	O
at	O
Imperial	O
College	O
)	O
and	O
it	O
is	O
the	O
basis	O
for	O
almost	O
all	O
other	O
color	B-Algorithm
spaces	I-Algorithm
.	O
</s>
<s>
The	O
CIERGB	O
color	B-Algorithm
space	I-Algorithm
is	O
a	O
linearly-related	O
companion	O
of	O
CIE	O
XYZ	O
.	O
</s>
<s>
RGBA	O
is	O
RGB	O
with	O
an	O
additional	O
channel	B-Algorithm
,	O
alpha	O
,	O
to	O
indicate	O
transparency	O
.	O
</s>
<s>
Common	O
color	B-Algorithm
spaces	I-Algorithm
based	O
on	O
the	O
RGB	O
model	O
include	O
sRGB	O
,	O
Adobe	O
RGB	O
,	O
ProPhoto	O
RGB	O
,	O
scRGB	B-Device
,	O
and	O
CIE	O
RGB	O
.	O
</s>
<s>
CMYK	O
uses	O
subtractive	O
color	O
mixing	O
used	O
in	O
the	O
printing	O
process	O
,	O
because	O
it	O
describes	O
what	O
kind	O
of	O
inks	B-Application
need	O
to	O
be	O
applied	O
so	O
the	O
light	O
reflected	O
from	O
the	O
substrate	O
and	O
through	O
the	O
inks	B-Application
produces	O
a	O
given	O
color	O
.	O
</s>
<s>
)	O
,	O
and	O
uses	O
ink	B-Application
to	O
subtract	O
color	O
from	O
white	O
to	O
create	O
an	O
image	O
.	O
</s>
<s>
CMYK	O
stores	O
ink	B-Application
values	O
for	O
cyan	O
,	O
magenta	B-Algorithm
,	O
yellow	O
and	O
black	O
.	O
</s>
<s>
There	O
are	O
many	O
CMYK	O
color	B-Algorithm
spaces	I-Algorithm
for	O
different	O
sets	O
of	O
inks	B-Application
,	O
substrates	O
,	O
and	O
press	O
characteristics	O
(	O
which	O
change	O
the	O
dot	O
gain	O
or	O
transfer	O
function	O
for	O
each	O
ink	B-Application
and	O
thus	O
change	O
the	O
appearance	O
)	O
.	O
</s>
<s>
It	O
is	O
similar	O
to	O
the	O
YUV	O
scheme	O
used	O
in	O
most	O
video	O
capture	O
systems	O
and	O
in	O
PAL	B-Language
(	O
Australia	O
,	O
Europe	O
,	O
except	O
France	O
,	O
which	O
uses	O
SECAM	O
)	O
television	O
,	O
except	O
that	O
the	O
YIQ	O
color	B-Algorithm
space	I-Algorithm
is	O
rotated	O
33°	O
with	O
respect	O
to	O
the	O
YUV	O
color	B-Algorithm
space	I-Algorithm
and	O
the	O
color	O
axes	O
are	O
swapped	O
.	O
</s>
<s>
It	O
is	O
most	O
commonly	O
seen	O
in	O
its	O
digital	B-General_Concept
form	O
,	O
YCbCr	O
,	O
used	O
widely	O
in	O
video	O
and	O
image	B-General_Concept
compression	I-General_Concept
schemes	O
such	O
as	O
MPEG	O
and	O
JPEG	O
.	O
</s>
<s>
xvYCC	O
is	O
a	O
new	O
international	O
digital	B-General_Concept
video	O
color	B-Algorithm
space	I-Algorithm
standard	O
published	O
by	O
the	O
IEC	O
(	O
IEC	O
61966-2-4	O
)	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
the	O
ITU	O
BT.601	O
and	O
BT.709	B-Device
standards	O
but	O
extends	O
the	O
gamut	O
beyond	O
the	O
R/G/B	O
primaries	O
specified	O
in	O
those	O
standards	O
.	O
</s>
<s>
HSV	O
(	O
hue	B-Language
,	O
saturation	O
,	O
value	O
)	O
,	O
also	O
known	O
as	O
HSB	O
(	O
hue	B-Language
,	O
saturation	O
,	O
brightness	O
)	O
is	O
often	O
used	O
by	O
artists	O
because	O
it	O
is	O
often	O
more	O
natural	O
to	O
think	O
about	O
a	O
color	O
in	O
terms	O
of	O
hue	B-Language
and	O
saturation	O
than	O
in	O
terms	O
of	O
additive	O
or	O
subtractive	O
color	B-Algorithm
components	I-Algorithm
.	O
</s>
<s>
HSV	O
is	O
a	O
transformation	O
of	O
an	O
RGB	O
color	B-Algorithm
space	I-Algorithm
,	O
and	O
its	O
components	O
and	O
colorimetry	O
are	O
relative	O
to	O
the	O
RGB	O
color	B-Algorithm
space	I-Algorithm
from	O
which	O
it	O
was	O
derived	O
.	O
</s>
<s>
HSL	O
(	O
hue	B-Language
,	O
saturation	O
,	O
lightness/luminance	O
)	O
,	O
also	O
known	O
as	O
HLS	O
or	O
HSI	O
(	O
hue	B-Language
,	O
saturation	O
,	O
intensity	O
)	O
is	O
quite	O
similar	O
to	O
HSV	O
,	O
with	O
"	O
lightness	O
"	O
replacing	O
"	O
brightness	O
"	O
.	O
</s>
<s>
The	O
RG	O
Chromaticity	O
space	O
is	O
used	O
in	O
computer	B-Application
vision	I-Application
applications	O
.	O
</s>
<s>
The	O
TSL	O
color	B-Algorithm
space	I-Algorithm
(	O
Tint	O
,	O
Saturation	O
and	O
Luminance	O
)	O
is	O
used	O
in	O
face	B-General_Concept
detection	I-General_Concept
.	O
</s>
<s>
Early	O
color	B-Algorithm
spaces	I-Algorithm
had	O
two	O
components	O
.	O
</s>
<s>
In	O
color	O
science	O
,	O
there	O
are	O
two	O
meanings	O
of	O
the	O
term	O
absolute	O
color	B-Algorithm
space	I-Algorithm
:	O
</s>
<s>
A	O
color	B-Algorithm
space	I-Algorithm
in	O
which	O
the	O
perceptual	O
difference	O
between	O
colors	O
is	O
directly	O
related	O
to	O
distances	O
between	O
colors	O
as	O
represented	O
by	O
points	O
in	O
the	O
color	B-Algorithm
space	I-Algorithm
,	O
i.e.	O
</s>
<s>
a	O
uniform	O
color	B-Algorithm
space	I-Algorithm
.	O
</s>
<s>
A	O
color	B-Algorithm
space	I-Algorithm
in	O
which	O
colors	O
are	O
unambiguous	O
,	O
that	O
is	O
,	O
where	O
the	O
interpretations	O
of	O
colors	O
in	O
the	O
space	O
are	O
colorimetrically	O
defined	O
without	O
reference	O
to	O
external	O
factors	O
.	O
</s>
<s>
CIEXYZ	O
,	O
sRGB	O
,	O
and	O
ICtCp	B-Device
are	O
examples	O
of	O
absolute	O
color	B-Algorithm
spaces	I-Algorithm
,	O
as	O
opposed	O
to	O
a	O
generic	O
RGB	O
color	B-Algorithm
space	I-Algorithm
.	O
</s>
<s>
A	O
non-absolute	O
color	B-Algorithm
space	I-Algorithm
can	O
be	O
made	O
absolute	O
by	O
defining	O
its	O
relationship	O
to	O
absolute	O
colorimetric	O
quantities	O
.	O
</s>
<s>
The	O
CIE	O
1976	O
L*	O
,	O
a*	O
,	O
b*	O
color	B-Algorithm
space	I-Algorithm
is	O
sometimes	O
referred	O
to	O
as	O
absolute	O
,	O
though	O
it	O
also	O
needs	O
a	O
white	O
point	O
specification	O
to	O
make	O
it	O
so	O
.	O
</s>
<s>
A	O
popular	O
way	O
to	O
make	O
a	O
color	B-Algorithm
space	I-Algorithm
like	O
RGB	O
into	O
an	O
absolute	O
color	O
is	O
to	O
define	O
an	O
ICC	O
profile	O
,	O
which	O
contains	O
the	O
attributes	O
of	O
the	O
RGB	O
.	O
</s>
<s>
A	O
color	O
in	O
one	O
absolute	O
color	B-Algorithm
space	I-Algorithm
can	O
be	O
converted	O
into	O
another	O
absolute	O
color	B-Algorithm
space	I-Algorithm
,	O
and	O
back	O
again	O
,	O
in	O
general	O
;	O
however	O
,	O
some	O
color	B-Algorithm
spaces	I-Algorithm
may	O
have	O
gamut	O
limitations	O
,	O
and	O
converting	O
colors	O
that	O
lie	O
outside	O
that	O
gamut	O
will	O
not	O
produce	O
correct	O
results	O
.	O
</s>
<s>
One	O
part	O
of	O
the	O
definition	O
of	O
an	O
absolute	O
color	B-Algorithm
space	I-Algorithm
is	O
the	O
viewing	O
conditions	O
.	O
</s>
<s>
Occasionally	O
,	O
there	O
are	O
precise	O
rules	O
for	O
converting	O
between	O
non-absolute	O
color	B-Algorithm
spaces	I-Algorithm
.	O
</s>
<s>
However	O
,	O
in	O
general	O
,	O
converting	O
between	O
two	O
non-absolute	O
color	B-Algorithm
spaces	I-Algorithm
(	O
for	O
example	O
,	O
RGB	O
to	O
CMYK	O
)	O
or	O
between	O
absolute	O
and	O
non-absolute	O
color	B-Algorithm
spaces	I-Algorithm
(	O
for	O
example	O
,	O
RGB	O
to	O
L*a*b*	O
)	O
is	O
almost	O
a	O
meaningless	O
concept	O
.	O
</s>
<s>
A	O
different	O
method	O
of	O
defining	O
absolute	O
color	B-Algorithm
spaces	I-Algorithm
is	O
familiar	O
to	O
many	O
consumers	O
as	O
the	O
swatch	O
card	O
,	O
used	O
to	O
select	O
paint	O
,	O
fabrics	O
,	O
and	O
the	O
like	O
.	O
</s>
<s>
A	O
more	O
standardized	O
method	O
of	O
defining	O
absolute	O
colors	O
is	O
the	O
Pantone	O
Matching	O
System	O
,	O
a	O
proprietary	O
system	O
that	O
includes	O
swatch	O
cards	O
and	O
recipes	O
that	O
commercial	O
printers	O
can	O
use	O
to	O
make	O
inks	B-Application
that	O
are	O
a	O
particular	O
color	O
.	O
</s>
