Color

< Visuals | Graphics >

Using Colors

Using colors with ConTeXt is easy:

• Start with \setupcolors[state=start]. Without that, everything appears in greys.
• If you want only RGB or only CMYK color, use cmyk=no or rgb=no. Multitone colors see below. Perhaps that covers spot colors and hexachrome also.
• Normally all colors are defined in RGB and CMYK and get converted if needed.
• You find lists of predefined colors in the files colo-xxx.tex, load them with \setupcolor[xxx]:
  • rgb: some simple colors, loaded by default (with translations for the different interface languages!)
  • xwi: X-Windows-colors
  • pra: PRAGMA ADE company colors
  • ema: Emacs colors
• Try the magic \showcolor[xxx]!
• Define your own colors with \definecolor[blablue][r=.1, g=.1, b=1, c=1, m=.1, y=0, k=0, s=.2] (definition for RGB, CMYK and Grey!)
• You can define transparent colors through setting t, e.g. t=0.5. Beware, most PDF viewers and printshops can't handle PDF transparences!
• Use the color name like [color=blablue] in some \setup... command.
• Typeset single text elements with \color[blablue]{nice blue text} or longer sections with \startcolor[blablue] ... \stopcolor.

(See also "Color and Background" in the manual!)

Sample

\setupcolors[state=start]
\definecolor[blablue][r=.25, g=.1, b=1, c=1, m=.1, y=0, k=0, s=.2]

Here's some \color[blablue]{blue text} inbetween!

\showcolor[rgb]

Colorgroups and Palettes

\definecolorgroup[name][system][values]

\definepalet[palettename][colorname1=groupcolor:1, colorname2=groupcolor:2, ...]

Very interesting feature, to be described later... (see manual)

Multitones

Hans wrote on the mailinglist on 2004-12-27 about handling of multitone colors:

Currently it's done by pdftools.rb

Once pdfxTeX becomes pdfeTeX out of a sudden your beta can do it as well.

I still need to figure out a way to automatically reverse the graphic, but one of these days you can start using it.

Actually, multitones for text already work out of the box:

\setupcolors[state=start]

\definecolor [blue]   [c=1,m=.38,y=0,k=.64]
\definecolor [yellow] [c=0,m=.28,y=1,k=.06]

\definecolor [blue-100]   [blue]   [p=1]
\definecolor [yellow-100] [yellow] [p=1]

\definemultitonecolor [combicolor]   [blue=.12,yellow=.28] [c=.1,m=.1,y=.3,k=.1]

\starttext

\startcolor[blue]\blackrule[width=3cm,height=3cm]\stopcolor

\startcolor[yellow]\blackrule[width=3cm,height=3cm]\stopcolor

\startcolor[combicolor]\blackrule[width=3cm,height=3cm]\stopcolor

\stoptext

(The CMYK color spec is the fall back color used on screen; one can preview separations in full Acrobat 7.)