function ColorDarken($color, $dif=20){ $color = str_replace('#', '', $color); if (strlen($color) != 6){ return '000000'; } $rgb = ''; for ($x=0;$x<3;$x++){ $c = hexdec(substr($color,(2*$x),2)) - $dif; $c = ($c < 0) ? 0 : dechex($c); $rgb .= (strlen($c) < 2) ? '0'.$c : $c; } return '#'.$rgb; } //Example: for ($x=1; $x < 20; $x++){ // Start color: $c = ColorDarken('#FF481D', ($x * 3)); print "<div style='background-color: $c; color: $c; font-size: 50%; padding: 0px;'>.</div>\n"; }