Perforated plates (10) for use as filter media and devices for fluid injection and extrusion have a multiplicity of holes (14) of a uniform size and a selected diameter as small as 0.5 micron. The plates are made by a "wire drawing" process wherein a sacrificial wire material in plate metal can is repeatedly extruded and restacked, elongating the wire and reducing its diameter. Plates are then cut from the extruded composite, and the wire metal is removed by selective etching (Fig. 8). By use of this process, perforated plates with several features unavailable previously are obtained. In particular, the plates have much smaller holes, higher porosity, and uniform size and shape, along with any desired thickness and a high length-to-diameter ratio. Such plates are ideally suited for use as a medium for various types of filters where removal of contaminants sized in the lower micron range is desired. Size and distribution of the holes in the plate are precisely controllable, enabling separations of materials of specific sizes.