Color Names

Example Usage • Color Model Specification • List of Color Names

A number of ImageMagick options and methods take a color as an argument. The color can then be given as a color name (there is a limited but large set of these; see below) or it can be given as a set of numbers (in decimal or hexadecimal), each corresponding to a channel in an RGB or RGBA color model. HSL, HSLA, HSB, HSBA, CMYK, or CMYKA color models may also be specified. These topics are briefly described in the sections below.

Use the Color Converter to supply any valid ImageMagick color specification as described below to see a color swatch of that color and to convert to all the other color models.

Example Usage

Each of the following commands produces the same lime border around the image. (Use "double quotes" for Windows.)

convert -bordercolor lime -border 10 image.jpg image.png
convert -bordercolor '#0f0' -border 10 image.jpg image.png
convert -bordercolor '#00ff00' -border 10 image.jpg image.png
convert -bordercolor 'rgb(0,255,0)' -border 10 image.jpg image.png
convert -bordercolor 'rgb(0,100%,0)' -border 10 image.jpg image.png

The list of recognized color names (for example, aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, yellow, and others) is shown in a table further below.

Color Model Specification

The sRGB, CMYK, HSL and HSB color models are used in numerical color specifications. These examples all specify the same red sRGB color:

#f00                       4-bit  #rgb
#ff0000                    8-bit  #rrggbb
#ff0000ff                  8-bit  #rrggbbaa
#fff000000                12-bit  #rrrgggbbb
#ffff00000000             16-bit  #rrrrggggbbbb
#ffff00000000ffff         16-bit  #rrrrggggbbbbaaaa
#ffffffff0000000000000000ffffffff 
                          32-bit  #rrrrrrrrggggggggbbbbbbbbaaaaaaaa
rgb(255, 0, 0)            an integer in the range 0—255 for each component
rgb(100.0%, 0.0%, 0.0%)   a float in the range 0—100% for each component

The format of an sRGB value in hexadecimal notation is a '#' immediately followed by 3-32 hexadecimal characters. The three-digit sRGB notation (#rgb) is converted into six-digit form (#rrggbb) by replicating digits, not by adding zeros. For example, #fb0 expands to #ffbb00. This ensures that white (#ffffff) can be specified with the short notation (#fff) and removes any dependencies on the color depth of the image. Use the hexadecimal notation whenever performance is an issue. ImageMagick does not need to load the expansive color table to interpret a hexadecimal color, e.g., #000000, but it does if black is used instead.

The format of an sRGB value in the functional notation is 'rgb(r,g,b)', where r, g, and b are either three integer or float values in the range 0—255 or three integer or float percentage values in the range 0—100%. The value 255 corresponds to 100%, and to #F or #FF in the hexadecimal notation: rgb(255, 255, 255) = rgb(100%, 100%, 100%) = #FFF = #FFFFFF.

Note, as of ImageMagick 6.9.11-53, the commas are no longer necessary and a slash can proceed the alpha value, e.g. rgb(255 128 0 / 50%)..

White space characters are allowed around the numerical values, at least if the entire color argument is enclosed in quotes ('single quotes' for Linux-like systems, "double quotes" for Windows).

The sRGB color model is extended in this specification to include alpha to allow specification of the transparency of a color. These examples all specify the same color:

rgb(255, 0, 0)                 range 0 - 255
rgba(255, 0, 0, 1.0)           the same, with an explicit alpha value
rgb(100%, 0%, 0%)              range 0.0% - 100.0%
rgba(100%, 0%, 0%, 1.0)        the same, with an explicit alpha value

The format of an RGBA value in the functional notation is 'rgba(r,g,b,a)', where r, g, and b are as described above for the RGB functional notation, and where the alpha value a ranges from 0.0 (fully transparent) to 1.0 (fully opaque).

There is also a color called 'none' that is fully transparent. This color is shorthand for rgba(0, 0, 0, 0.0).

Non-linear gray values are conveniently defined with a name, single intensity value or an intensity value and an alpha value:

gray50            near mid gray
gray(127)         near mid gray
gray(50%)         mid gray
graya(50%, 0.5)   semi-transparent mid gray

For linear gray values add -colorspace RGB -colorspace Gray or -colorspace LinearGray when creating gray colors. The latter is new as of Imagemagick 6.9.9-29 and 7.0.7-17.

The ImageMagick color model also supports hue-saturation-lightness (HSL) and hue-saturation-brightness (HSB) colors as a complement to numerical sRGB colors. HSL colors are encoding as a triple (hue, saturation, lightness). Likewise HSB colors are encoding as a triple (hue, saturation, brightness). HSL or HSB triples are either direct values (hue 0—360, saturation 0—255, lightness or brightness 0—255) or with S,L,B as percentage values relative to these ranges.

The HSB color system is geometrically represented as a cone with its apex pointing downward. Hue is measured around the perimeter. Saturation is measured from the axis outward. Brightness is measured from the apex upward.

The HSL color system is geometrically represented as a stacked double cone with one apex pointing downward and the other pointing upward. The widest ends of both cones are stacked together one on top of the other. Hue is measured around the perimeter. Saturation is measured from the axis outward. Lightness is measured from the bottom apex upward.

See http://en.wikipedia.org/wiki/HSL_and_HSV for more details on HSL and HSB color systems.

Hue is represented as an angle of the color around the circular perimeter of the cone(s) (i.e. the rainbow represented in a circle). Hue values are integers or floats in the range 0—360. By definition red=0=360, and the other colors are spread around the circle, so green=120, blue=240, etc. As an angle, it implicitly wraps around such that -120=240 and 480=120, for instance. (Students of trigonometry would say that "coterminal angles are equivalent" here; an angle θ can be standardized by computing the equivalent angle, θ mod 360.)

Saturation is measure outward from the central axis of the cone(s) toward the perimeter of the cone(s). Saturation may be expressed as an integer or float in the range 0—255 or as an integer or float percentage in the range 0—100. Saturation may be thought of as the absence of any "white" mixed with the base color. Thus 255 or 100% is full saturation and corresponds to a point on the outside surface of the cone (HSB) or double cone (HSL). It will be the most "colorful" region. 0 or 0% is no saturation which results in some shade of gray. It occurs along the central axis of the cone or double cone with black at the bottom apex and white at the top.

Brightness and Lightness also may be represented as integers or floats in the range 0—255 or as integer or float percentages in the range 0—100%. Brightness and Lightness are measured from the bottom apex upward to the top of the cone or double cone along the cone(s) central axis. 0 or 0% corresponds to the bottom apex and 255 or 100% corresponds to the top center of the cone for Brightness and to the top apex of the double cone for Lightness.

The HSB color system is a little easier to understand than the HSL color system. In the HSB color system, black is at the bottom apex and white is at the top center of the cone on the central axis. The most colorful or saturated colors will then be at the outer edge of the top of the cone at the widest part. Thus at Saturation=100% and Brightness=100%

hsb(0,   100%,  100%)    or    hsb(0,   255,   255)       full red
hsb(120, 100%,  100%)    or    hsb(120, 255,   255)       full green
hsb(120, 100%,  75%)     or    hsb(120, 255,   191.25)    medium green
hsb(120, 100%,  50%)     or    hsb(120, 255,   127.5)     dark green
hsb(120, 100%,  25%)     or    hsb(120, 255,   63.75)     very dark green
hsb(120, 50%,   50%)     or    hsb(120, 127.5, 127.5)     pastel green

In the HSL color system, black is at the bottom apex and white is at the top apex. However, saturation is largest at the middle of the double cone on its outer perimeter and thus at a lightness value of 50%. The most colorful or saturated colors will then be at the outer edge of the double cone at its widest part. Thus at Saturation=100% and Brightness=50%.

hsl(0,   100%,  50%)     or    hsl(0,   255,   127.5)     full red
hsl(120, 100%,  100%)    or    hsl(120, 255,   255)       white
hsl(120, 100%,  75%)     or    hsl(120, 255,   191.25)    pastel green
hsl(120, 100%,  50%)     or    hsl(120, 255,   127.5)     full green
hsl(120, 100%,  25%)     or    hsl(120, 255,   63.75)     dark green
hsl(120, 50%,   50%)     or    hsl(120, 127.5, 127.5)     medium green

One advantage of HSB or HSL over RGB is that it can be more intuitive: you can guess at the colors you want, and then tweak. It is also easier to create sets of matching colors (by keeping the hue the same and varying the brightness or lightness and saturation, for example).

Just as the 'rgb()' functional notation has the 'rgba()' alpha counterpart, the 'hsl()' and 'hsb()' functional notations have their 'hsla()' 'hsba()' alpha counterparts. These examples specify the same color:

hsb(120, 100%,  100%)              full green in hsb
hsba(120, 100%,  100%,  1.0)       the same, with an alpha value of 1.0
hsb(120, 255,  255)                full green in hsb
hsba(120, 255,  255,  1.0)         the same, with an alpha value of 1.0

hsl(120, 100%,  50%)               full green in hsl
hsla(120, 100%,  50%,  1.0)        the same, with an alpha value of 1.0
hsl(120, 255,  127.5)              full green in hsl
hsla(120, 255,  127.5,  1.0)       the same, with an alpha value of 1.0

For ImageMagick between 6.5.6-6 and 6.9.2-0, HSL (HSB) could only be specified with Hue as percent in range 0—100%, when Saturation and Lightness (Brightness) were also specified as percent in range 0—100%.

Specify the Lab colors like this:

cielab(62.253188, 23.950124, 48.410653)

Note, the a and b components of any Lab color you specify are biased internally by 50% to ensure it fits in the quantum range (typically 0 to 65535). The bias is retained when writing to the TIFF and MIFF image formats. However, the TXT format supports negative pixel values so the bias is removed when writing to this format:

$ convert xc:#CD853F -colorspace LAB txt:
# ImageMagick pixel enumeration: 1,1,65535,cielab
0,0: (40470.8,38266.6,12314.5)  #9E17957BB01A  cielab(61.7544,21.3973,47.9163)

$ convert xc:"cielab(61.7544,21.3973,47.9163)" -colorspace sRGB -depth 8 peru.png

Or specify colors generically with the icc-color keyword, for example:

icc-color(cmyk, 0.11, 0.48, 0.83, 0.00)  cymk
icc-color(rgb, 1, 0, 0)                  linear rgb
icc-color(rgb, red)                      linear rgb
icc-color(lineargray, 0.5)               linear gray
icc-color(srgb, 1, 0, 0)                 non-linear rgb
icc-color(srgb, red)                     non-linear rgb
icc-color(gray, 0.5)                     non-linear gray

Or specify uncalibrated device colors with the device- keyword, for example:

device-gray(0.5)
device-rgb(0.5, 1.0, 0.0)
device-cmyk(0.11, 0.48, 0.83, 0.00)

ImageMagick also supports wide-gamut color such as Lab, LC H, and Display-P3.

List of Color Names

The table below provides a list of named colors recognized by ImageMagick: