X11 color names

In computing, on the X Window System, X11 color names are represented in a simple text file, which maps certain strings to RGB color values. It is shipped with every "X" installation, hence the name, and is usually located in <X11root>/lib/X11/rgb.txt.^[1]

It is not known who originally compiled the list. The list shows a continuity neither in selected color values nor in color names, and many color triplets have multiple names. Despite this, graphic designers and others got used to them, making it practically impossible to introduce a more stringent and logical alias list.

The first versions of Mosaic and Netscape Navigator used the X11 colors as the basis for the Web colors list, as both were originally X applications.

Contents 1 Charts 1.1 Color names that clash between X11 and HTML/CSS 1.2 Color names identical between X11 and HTML/CSS 2 Shades of gray 3 Color variations 4 See also 5 References 6 External links

Charts

These charts are not a standard set of colors to be found on any X Window system. Rather it is the standardised "X11 colors" accepted by browsers following the HTML and CSS standards. This set is cut down and rationalised, and has a few differences from a typical rgb.txt file (especially, Green is different).^[2] RGB values shown are normalised to the range 0 to 255.

Almost the exact same color names are used in .NET Framework, in the KnownColor and Color enumerations. The only color difference is DarkSeaGreen which is defined as 8F,BC,8B (instead of 8F,BC,8F).

Color names that clash between X11 and HTML/CSS

Perhaps most unusual of the color clashes is the case of "gray." In HTML, "gray" is specifically reserved for 127,127,127. However, in X11, "gray" was assigned to 190,190,190 (close to HTML's "silver"), and had "lightgray" (211,211,211) and "darkgray" (169,169,169) counterparts. This resulted in HTML's "gray," at 127, actually being significantly darker than "darkgray," at 169.

Color name	X11 color								HTML and CSS color
	Sample	Components (red, green, blue)							Sample	Components (red, green, blue)
		hex.				dec.				hex.				dec.
Gray		BE	BE	BE		190	190	190		7F	7F	7F		127	127	127
Green		00	FF	00		0	255	0		00	7F	00		0	127	0
Maroon		B0	30	60		176	48	96		7F	00	00		127	0	0
Purple		A0	20	F0		160	32	240		7F	00	7F		127	0	127

Color names identical between X11 and HTML/CSS

Color name	Sample	Components (red, green, blue)
		hexadecimal				decimal
Alice Blue		F0	F8	FF		240	248	255
Antique White		FA	EB	D7		250	235	215
Aqua		00	FF	FF		0	255	255
Aquamarine		7F	FF	D4		127	255	212
Azure		F0	FF	FF		240	255	255
Beige		F5	F5	DC		245	245	220
Bisque		FF	E4	C4		255	228	196
Black		00	00	00		0	0	0
Blanched Almond		FF	EB	CD		255	235	205
Blue		00	00	FF		0	0	255
Blue Violet		8A	2B	E2		138	43	226
Brown		A5	2A	2A		165	42	42
Burlywood		DE	B8	87		222	184	135
Cadet Blue		5F	9E	A0		95	158	160
Chartreuse		7F	FF	00		127	255	0
Chocolate		D2	69	1E		210	105	30
Coral		FF	7F	50		255	127	80
Cornflower		64	95	ED		100	149	237
Cornsilk		FF	F8	DC		255	248	220
Crimson		DC	14	3C		220	20	60
Cyan		00	FF	FF		0	255	255
Dark Blue		00	00	8B		0	0	139
Dark Cyan		00	8B	8B		0	139	139
Dark Goldenrod		B8	86	0B		184	134	11
Dark Gray		A9	A9	A9		169	169	169
Dark Green		00	64	00		0	100	0
Dark Khaki		BD	B7	6B		189	183	107
Dark Magenta		8B	00	8B		139	0	139
Dark Olive Green		55	6B	2F		85	107	47
Dark Orange		FF	8C	00		255	140	0
Dark Orchid		99	32	CC		153	50	204
Dark Red		8B	00	00		139	0	0
Dark Salmon		E9	96	7A		233	150	122
Dark Sea Green		8F	BC	8F		143	188	143
Dark Slate Blue		48	3D	8B		72	61	139
Dark Slate Gray		2F	4F	4F		47	79	79
Dark Turquoise		00	CE	D1		0	206	209
Dark Violet		94	00	D3		148	0	211
Deep Pink		FF	14	93		255	20	147
Deep Sky Blue		00	BF	FF		0	191	255
Dim Gray		69	69	69		105	105	105
Dodger Blue		1E	90	FF		30	144	255
Firebrick		B2	22	22		178	34	34
Floral White		FF	FA	F0		255	250	240
Forest Green		22	8B	22		34	139	34
Fuchsia		FF	00	FF		255	0	255
Gainsboro		DC	DC	DC		220	220	220
Ghost White		F8	F8	FF		248	248	255
Gold		FF	D7	00		255	215	0
Goldenrod		DA	A5	20		218	165	32
Gray	clash between X11 and HTML/CSS - See previous table
Green	clash between X11 and HTML/CSS - See previous table
Green Yellow		AD	FF	2F	173	255	47
Honeydew		F0	FF	F0	240	255	240
Hot Pink		FF	69	B4	255	105	180
Indian Red		CD	5C	5C	205	92	92
Indigo		4B	00	82	75	0	130
Ivory		FF	FF	F0	255	255	240
Khaki		F0	E6	8C	240	230	140
Lavender		E6	E6	FA	230	230	250
Lavender Blush		FF	F0	F5	255	240	245
Lawn Green		7C	FC	00	124	252	0
Lemon Chiffon		FF	FA	CD	255	250	205
Light Blue		AD	D8	E6	173	216	230
Light Coral		F0	80	80	240	128	128
Light Cyan		E0	FF	FF	224	255	255
Light Goldenrod		FA	FA	D2	250	250	210
Light Green		90	EE	90	144	238	144
Light Gray		D3	D3	D3	211	211	211
Light Pink		FF	B6	C1	255	182	193
Light Salmon		FF	A0	7A	255	160	122
Light Sea Green		20	B2	AA	32	178	170
Light Sky Blue		87	CE	FA	135	206	250
Light Slate Gray		77	88	99	119	136	153
Light Steel Blue		B0	C4	DE	176	196	222
Light Yellow		FF	FF	E0	255	255	224
Lime		00	FF	00	0	255	0
Lime Green		32	CD	32	50	205	50
Linen		FA	F0	E6	250	240	230
Magenta		FF	00	FF	255	0	255
Maroon	clash between X11 and HTML/CSS - See previous table
Medium Aquamarine		66	CD	AA	102	205	170
Medium Blue		00	00	CD	0	0	205
Medium Orchid		BA	55	D3	186	85	211
Medium Purple		93	70	DB	147	112	219
Medium Sea Green		3C	B3	71	60	179	113
Medium Slate Blue		7B	68	EE	123	104	238
Medium Spring Green		00	FA	9A	0	250	154
Medium Turquoise		48	D1	CC	72	209	204
Medium Violet Red		C7	15	85	199	21	133
Midnight Blue		19	19	70	25	25	112
Mint Cream		F5	FF	FA	245	255	250
Misty Rose		FF	E4	E1	255	228	225
Moccasin		FF	E4	B5	255	228	181
Navajo White		FF	DE	AD	255	222	173
Navy		00	00	80	0	0	128
Old Lace		FD	F5	E6	253	245	230
Olive		80	80	00	128	128	0
Olive Drab		6B	8E	23	107	142	35
Orange		FF	A5	00	255	165	0
Orange Red		FF	45	00	255	69	0
Orchid		DA	70	D6	218	112	214
Pale Goldenrod		EE	E8	AA	238	232	170
Pale Green		98	FB	98	152	251	152
Pale Turquoise		AF	EE	EE	175	238	238
Pale Violet Red		DB	70	93	219	112	147
Papaya Whip		FF	EF	D5	255	239	213
Peach Puff		FF	DA	B9	255	218	185
Peru		CD	85	3F	205	133	63
Pink		FF	C0	CB	255	192	203
Plum		DD	A0	DD	221	160	221
Powder Blue		B0	E0	E6	176	224	230
Purple	clash between X11 and HTML/CSS - See previous table
Red		FF	00	00	255	0	0
Rosy Brown		BC	8F	8F	188	143	143
Royal Blue		41	69	E1	65	105	225
Saddle Brown		8B	45	13	139	69	19
Salmon		FA	80	72	250	128	114
Sandy Brown		F4	A4	60	244	164	96
Sea Green		2E	8B	57	46	139	87
Seashell		FF	F5	EE	255	245	238
Sienna		A0	52	2D	160	82	45
Silver		C0	C0	C0	192	192	192
Sky Blue		87	CE	EB	135	206	235
Slate Blue		6A	5A	CD	106	90	205
Slate Gray		70	80	90	112	128	144
Snow		FF	FA	FA	255	250	250
Spring Green		00	FF	7F	0	255	127
Steel Blue		46	82	B4	70	130	180
Tan		D2	B4	8C	210	180	140
Teal		00	80	80	0	128	128
Thistle		D8	BF	D8	216	191	216
Tomato		FF	63	47	255	99	71
Turquoise		40	E0	D0	64	224	208
Violet		EE	82	EE	238	130	238
Wheat		F5	DE	B3	245	222	179
White		FF	FF	FF	255	255	255
White Smoke		F5	F5	F5	245	245	245
Yellow		FF	FF	00	255	255	0
Yellow Green		9A	CD	32	154	205	50

Shades of gray

The list shown above covers only the colors supported by popular browsers as defined for JavaScript 1.1^[3] and before. Some browsers like Netscape navigator insisted on an a in any gray except for lightgrey.

The complete rgb.txt defines 101 shades from gray0 (black) up to gray100 (white) in addition to gray and its variants listed above.

The shades are apparently defined by the formula grayN := round(N*255/100) resulting in e.g. gray96 #F5F5F5 (245), which happens to be the same as WhiteSmoke. Similarly dimgray is the same as gray41 #696969 (105).

On the other hand gray #BEBEBE (190) lies between gray74 #BDBDBD (189) and gray75 #BFBFBF (191), darkgray #A9A9A9 (169) isn't the same as gray66 #A8A8A8 (168), and lightgrey #D3D3D3 (211) isn't the same as gray83 #D4D4D4 (212).

Color variations

For 78 colors as listed above, rgb.txt offers four variants "color1", "color2", "color3", and "color4", with "color1" corresponding to "color", so e.g. "snow1" is the same as "snow". These variations are neither supported by popular browsers nor adopted by W3C standards.

The formulae used to determine the RGB values for these variations appear to be somewhere near

color2 := color*93.2/100 (93%),

color3 := color*80.4/100 (80%),

color4 := color*54.8/100 (54%).

Examples

• 205.2=255*80.4/100 and 192.96=240*80.4/100 explain ivory3 #CDCDC1 (205 205 196) based on ivory #FFFFF0 (255 255 240),
• 139.74=255*54.8/100 and 131.52=240*54.8/100 are close to azure4 #838B8B (131 139 139) based on azure #F0FFFF (240 255 255),
• 237.66=255*93.2/100 yields yellow2 #EEEE00 (238 238 0) based on yellow #FFFF00 (255 255 0).

See also

• List of colors
• Web colors
• XPM (image format)

References

External links

• “SVG Color Keywords”, CSS Color Module Level 3, and “Recognized Color Keyword Names, SVG 1.1, two specifications of the W3C.
• X11 rgb.txt 1.1 at Xfree.86.org, 1994, and X11 rgb.txt 1.2, 2005 (excluding 96 aliases).
• “X11 Colors list for Mac OS X” – has a link to a Perl script to convert rgb.txt into a Mac OS X color picker (.clr) file, with or without duplicate names.
• Aubrey Jaffer. “Color-Name Dictionaries”. Jaffer’s self-published page includes extensive information about and comparisons between color-name dictionaries.

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