public static function cmy2cmyk( $cmy )
	{
		list( $c, $m, $y ) = $cmy;
		$k	= min( $c, $m, $y );
		$c	= ( $c - $k ) / ( 1 - $k );
		$m	= ( $m - $k ) / ( 1 - $k );
		$y	= ( $y - $k ) / ( 1 - $k );
		return array( $c, $m, $y, $k );
	}