A filter structure having a plurality of pores through the structure each of the pores having a cross section with a length (L) and a width (W) wherein the dimension of L is greater than the dimension of W. The filter can be used with an improved ink jet printhead having an ink inlet in one of its surfaces, a plurality of nozzles, individual channels connecting the nozzles to an internal ink supplying manifold, the manifold being supplied ink through the ink inlet, and selectively addressable heating elements for expelling ink droplets, the improved ink jet printhead comprising a substantially flat filter having predetermined dimensions and being bonded to the printhead containing the ink inlet, the filter having a plurality of pores, therethrough, each of the pores having a cross section with a length=L and a width=W, wherein the dimension of L is greater than the dimension of W. Also disclosed is a method for fabricating a filter element comprising the steps of positioning a thin polymer film in the output radiation path of an ablating laser, and controlling the laser output so that a plurality of pores are formed in portions of the polymer film, each of the pores having a cross section with a length (L) and a width (W), wherein the dimension of L is greater than the dimension of W.