Colour Examples

Some color definitions above and beyond what's standard in PmWiki:^[1]

%define=hardblue     color=#0000cc% hard blue
%define=darkgreen    color=#006400% dark green
%define=bluegrass    color=#009999% blue grass
%define=teal         color=#008080% teal
%define=darkpurple   color=#660066% dark purple
%define=perwinkle    color=#6600cc% periwinkle
%define=darkgrey     color=#a9a9a9% dark grey
%define=mistgreen    color=#669966% mist green
%define=slategreen   color=#669999% slate green
%define=lightpurple  color=#9966cc% light purple
%define=lightgrey    color=#999999% light grey
%define=lightblue    color=#add8e6% light blue
%define=springgreen  color=#00ff7f% spring green
%define=magenta      color=#ff00ff% magenta
%define=burntorange  color=#cc6633% burnt orange
%define=grey         color=#808080% grey
%define=lightgreen   color=#90ee90% light green
%define=pink         color=#ffc0cb% pink
%define=lightred     color=#ff6666% light red
%define=orange       color=#ffa500% orange
%define=lightorange  color=#ff9966% light orange
%define=gold         color=#ffd700% gold

hard blue dark green blue grass teal dark purple periwinkle dark grey mist green slate green light purple light grey light blue spring green magenta burnt orange grey light green pink light red orange light orange gold

Standard PmWiki colours

black	black
blue	blue
gray or grey	gray grey
green	green
maroon	maroon
navy	navy
purple	purple
red	red
silver	silver
white	white
yellow	yellow

Hints and Tips:

You need not "define" the hexadecimal colors in order to use them; it works just as well to set %color=#cc33cc% before some text as to "define" it and use the definition. The definition is convenient if you're going to use the color more than once.
Use lowercase characters - prevents color numbers being mis-read as Wiki text.
Remember that the same color may appear differently depending on the device (CRT screen, TFT display, printer, ...) and the gamma curve used. Notably, the same color may look too light or dark when seen on Windows (gamma is usually set to 2.5) and Mac computers (gamma 1.8).
Text color always looks brighter than background color, because the white background dominates the overall brightness. IOW text colors should be darker than background colors to achieve the same impression of brightness (unless, of course, your wiki has a reverse video color scheme).
Too many colours on the same page is distracting. Use them sparingly.
You can hide text by making it white-on-white. It's a poor obfuscation technique though: the HTML source code will give it away, and if a savvy visitor marks the text, he'll see it anyway. Still, some single-author sites use it for making the Edit link unobtrusive.

More Colours Options (external links open in new windows)

4096 Color Wheel
Websafe Color Chart at Mandarin Design
http://w3schools.com/html/html_colors.asp
Pixie download site - install and run this tiny Windows utility, and "simply point to a colour and it will tell you the hex, RGB, HTML, CMYK and HSV values of that colour." (on Macintosh just open TextEdit and use shift+command+c)

Comments

How do admins define colors for all pages?? Define color keywords and rely on the browser to render the color values. You can use the color keywords for both text color (use %keyword%text%%) and also background color (use %bgcolor=keyword%text%%). Add to your local configuration file:

$SVGColors = array (
'aliceblue','antiquewhite','aqua','aquamarine','azure','beige','bisque','black',
'blanchedalmond','blue','blueviolet','brown','burlywood','cadetblue','chartreuse','chocolate',
'coral','cornflowerblue','cornsilk','crimson','cyan','darkblue','darkcyan','darkgoldenrod',
'darkgrey','darkgreen','darkkhaki','darkmagenta','darkolivegreen','darkorange','darkorchid','darkred',
'darksalmon','darkseagreen','darkslateblue','darkslategray',
'darkturquoise','darkviolet','deeppink','deepskyblue',
'dimgray','dodgerblue','firebrick','floralwhite','forestgreen','fuchsia','gainsboro','ghostwhite',
'gold','goldenrod','gray','green','greenyellow','honeydew','hotpink','indianred',
'indigo','ivory','khaki','lavender','lavenderblush','lawngreen','lemonchiffon','lightblue',
'lightcoral','lightcyan','lightgoldenrodyellow','lightgreen',
'lightgrey','lightpink','lightsalmon','lightseagreen',
'lightskyblue','lightslategray','lightsteelblue','lightyellow','lime','limegreen','linen','magenta',
'maroon','mediumaquamarine','mediumblue','mediumorchid',
'mediumpurple','mediumseagreen','mediumslateblue','mediumspringgreen',
'mediumturquoise','mediumvioletred','midnightblue','mintcream',
'mistyrose','moccasin','navajowhite','navy',
'oldlace','olive','olivedrab','orange','orangered','orchid','palegoldenrod','palegreen',
'paleturquoise','palevioletred','papayawhip','peachbuff','peru','pink','plum','powderblue',
'purple','red','rosybrown','royalblue','saddlebrown','salmon','sandybrown','seagreen',
'seashell','sienna','silver','skyblue','slateblue','slategray','snow','springgreen',
'steelblue','tan','teal','thistle','tomato','turquoise','violet','wheat',
'white','whitesmoke','yellow','yellowgreen'
);
foreach($SVGColors as $c)
   $WikiStyle[$c]['color'] = $c;

Alternatively define the required colors in the local configuration file. (See Custom WikiStyles for details). For example add the following line(s) to local/config.php:

    $WikiStyle['hardblue']['color']    ='#0000cc';
    $WikiStyle['darkgreen']['color']   ='#006600';
    $WikiStyle['bluegrass']['color']   ='#009999';
    $WikiStyle['teal']['color']        ='#008080';
    $WikiStyle['darkpurple']['color']  ='#660066';
    $WikiStyle['perwinkle']['color']   ='#6600cc';
    $WikiStyle['darkgrey']['color']    ='#a9a9a9';
    $WikiStyle['mistgreen']['color']   ='#669966';
    $WikiStyle['slategreen']['color']  ='#669999';
    $WikiStyle['purple']['color']      ='#800080';
    $WikiStyle['lightpurple']['color'] ='#9966cc';
    $WikiStyle['lightgrey']['color']   ='#d3d3d3';
    $WikiStyle['lightblue']['color']   ='#add8e6';
    $WikiStyle['springgreen']['color'] ='#00ff7f';
    $WikiStyle['magenta']['color']     ='#ff00ff';
    $WikiStyle['burntorange']['color'] ='#cc6633';
    $WikiStyle['grey']['color']        ='#808080';
    $WikiStyle['lightgreen']['color']  ='#90ee90';
    $WikiStyle['pink']['color']        ='#ffc0cb';
    $WikiStyle['lightred']['color']    ='#ff6666';
    $WikiStyle['orange']['color']      ='#ffa500';
    $WikiStyle['lightorange']['color'] ='#ff9966';
    $WikiStyle['gold']['color']        ='#ffd700';
    $WikiStyle['yellow']['color']      ='#ffff00';

This page may have a more recent version on pmwiki.org: PmWiki:WikiStyleColors, and a talk page: PmWiki:WikiStyleColors-Talk.