LaTeX/Colors

Adding colors to your text is supported by the color package. Using this package, you can set the color of the font of the text, and set the background color of the page. You can use one of the predefined colors such as white, red, or yellow, or you can define your own named colors. It's also possible to color formulas in math-environments.

Adding the color package

To make use of these color features the color package must be inserted into the preamble.

\usepackage{color}

Alternatively, one can write:

\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}

The \usepackage is obvious, but the initialization of additional commands like usenames allows you to use names of the default colors, the same 16 base colors as used in HTML. The dvipsnames allows you access to more colors, another 64, and svgnames allows access to about 150 colors. The initialization of "table" allows colors to be added to tables by placing the color command just before the table. The package loaded here is the xcolor package.

If you need more colors, then you may also want to look at adding the x11names to the initialization section as well, this offers more than 300 colors, but you need to make sure your xcolor package is the most recent you can download.

Entering colored text

The simplest way to type colored text is by:

\textcolor{declared-color}{text}

where declared-color is a color that was defined before by \definecolor.

Another possible way by

{\color{declared-color} some text}

that will switch the standard text color to the color you want. It will work until the end of the current TeX group. For example:

\emph{some black text, {\color{red}followed by a red fragment}, going black again.}

The difference between \textcolor and \color is the same as that between \texttt and \ttfamily, you can use the one you prefer.

You can change the background color of the whole page by:

\pagecolor{declared-color}

Entering colored background for the text

\colorbox{declared-color}{text}

If the background color and the text color is changed, then:

\colorbox{declared-color1}{\color{declared-color2}text}

There is also \fcolorbox to make framed background color in yet another color:

\fcolorbox{declared-color-frame}{declared-color-background}{text}

Predefined colors

The predefined color names are

white, black, red, green, blue, cyan, magenta, yellow.

There may be other pre-defined colors on your system, but these should be available on all systems.

If you would like a color not pre-defined, you can use one of the 68 dvips colors, or define your own. These options are discussed in the following sections

The 68 standard colors known to dvips

Invoke the package with the usenames and dvipsnames option. If you are using tikz or pstricks package you must declare the color package before that, otherwise it will not work.

\usepackage[usenames,dvipsnames]{xcolor}

Name	Color		Name	Color
Apricot			Aquamarine
Bittersweet			Black
Blue			BlueGreen
BlueViolet			BrickRed
Brown			BurntOrange
CadetBlue			CarnationPink
Cerulean			CornflowerBlue
Cyan			Dandelion
DarkOrchid			Emerald
ForestGreen			Fuchsia
Goldenrod			Gray
Green			GreenYellow
JungleGreen			Lavender
LimeGreen			Magenta
Mahogany			Maroon
Melon			MidnightBlue
Mulberry			NavyBlue
OliveGreen			Orange
OrangeRed			Orchid
Peach			Periwinkle
PineGreen			Plum
ProcessBlue			Purple
RawSienna			Red
RedOrange			RedViolet
Rhodamine			RoyalBlue
RoyalPurple			RubineRed
Salmon			SeaGreen
Sepia			SkyBlue
SpringGreen			Tan
TealBlue			Thistle
Turquoise			Violet
VioletRed			White
WildStrawberry			Yellow
YellowGreen			YellowOrange

Defining new colors

If the predefined colors are not adequate, you may wish to define your own.

Place

Define the colors in the preamble of your document. (Reason: do so in the preamble, so that you can already refer to them in the preamble, which is useful, for instance, in an argument of another package that supports colors as arguments, such as the listings package.)

Method

In the abstract, the colors are defined following this scheme:

\definecolor{''name''}{''model''}{''color-spec''}

where:

• name is the name of the color; you can call it as you like
• model is the way you describe the color, and is one of gray, rgb and cmyk.
• color-spec is the description of the color

Color Models

Among the models you can use to describe the color are the following (several more are described in the xcolor manual):

Color Models

Model	Description	Color Specification	Example
gray	Shades of gray	Just one number between 0 (black) and 1 (white), so 0.95 will be very light gray, 0.30 will be dark gray.	\definecolor{light-gray}{gray}{0.95}
rgb	Red, Green, Blue	Three numbers given in the form red,green,blue; the quantity of each color is represented with a number between 0 and 1.	\definecolor{orange}{rgb}{1,0.5,0}
RGB	Red, Green, Blue	Three numbers given in the form red,green,blue; the quantity of each color is represented with a number between 0 and 255.	\definecolor{orange}{RGB}{255,127,0}
HTML	Red, Green, Blue	Six hexadecimal numbers given in the form RRGGBB; similar to what is used in HTML.	\definecolor{orange}{HTML}{FF7F00}
cmyk	Cyan, Magenta, Yellow, Black	Four numbers given in the form cyan,magenta,yellow,black; the quantity of each color is represented with a number between 0 and 1.	\definecolor{orange}{cmyk}{0,0.5,1,0}

Examples

To define a new color, follow the following example, which defines orange for you, by setting the red to the maximum, the green to one half (0.5), and the blue to the minimum:

\definecolor{orange}{rgb}{1,0.5,0}

The following code should give a similar results to the last code chunk.

\definecolor{orange}{RGB}{255,127,0}

If you loaded the xcolor package, you can define colors upon previously defined ones.

The first specifies 20 percent blue, the second is a mixture of 20 percent blue and 80 percent black and the last one is a mixture of (20*0.3) percent blue, (30*0.3) percent black and 70 percent green.

\color{blue!20} \color{blue!20!black} \color{blue!20!black!30!green}

xcolor also feature a handy command to define colors from color mixes:

\colorlet{notgreen}{blue!50!yellow}

Capturing colors

You may want to use colors that appear on other document, web pages, pictures, etc.

On Unix systems, you can use the small gcolor2 tool which will let you capture any color on screen.

When surfing on the web, you can get hexadecimal code for each color on a web page using the colorzilla extension to Firefox.

Sources

• The xcolor manual