Apparatus for and method of fully automatic rapid scanning and digitizing of an entire microscope sample, or a substantially large portion of a microscope sample, using a linear array detector synchronized with a positioning stage that is part of a computer controlled microscope slide scanner. The shade is fabricated from a bonded array of a predetermined number of stacked, identically shaped and sized, elements or preforms of uniform length corresponding to one of the height or width dimensions of the desired window covering. Data rates for the forward channel and the return channels may be selected from predefined combinations of forward and return channel data rates. This achieves the advantage that high-pressure fluctuations due to alternating modes are effectively prevented.