I was in a hurry and needed to guess the basic color of any hex value. Not precise and not the most elegant solution (color math is complicated!) but it is doing the job. public function guess_color($hex = '') { $hex = strtolower(str_replace('#', '', $hex)); $hex = str_replace(array('a','b','c','d','e','f'), '9', $hex); $r = $hex[0].$hex[1]; $g = $hex[2].$hex[3]; $b = $hex[4].$hex[5]; if($r-$g > 30 && $r-$b > 30) return 'red'; if($g-$r > 30 && $g-$b > 30) return 'green'; if($b-$r > 30 && $b-$g > 30) return 'blue'; if($r-$g 40) return 'yellow'; if($r-$b < 20 && ($r+$b)-($g*2) […]