private static function convertHexColorToRtf($color)
    {
        if (strlen($color) == 6) {
            $red    = hexdec(substr($color, 0, 2));
            $green  = hexdec(substr($color, 2, 2));
            $blue   = hexdec(substr($color, 4, 2));

            return '\red' . $red . '\green' . $green . '\blue' . $blue;
        }

        throw new PHPRtfLite_Exception('Color must be a hex number of length 3 or 6 digits! You gave me: #' . $color);
    }