One of the plates (6) is aligned with an alignment plate (16) having openings (4) corresponding with the alignment marks. The alignment plate is disposed on a table (2) having a source of back-lit light source (11) to illuminate the alignment marks from below.A front lit light source illuminates the marks from above. The alignment plate (16) have stops (17) to mechanically align the lower plate (6), the lower plate being held in place by vacuum. Both the back lit and front lit light sources may be cold light sources. Alignment may be facilitated using a television camera and monitor coupled to a microscope having an integral graticule. The plates (6) are metal and have alignment marks in the form of different shaped through holes.
