According to exemplary scanning devices herein, a platen has a sheet side and a scanner side, opposite the sheet side. A scanner is located on the scanner side of the transparent platen. The platen has a constant velocity transport (CVT) scanning position at an end of the platen. A portion of the platen, located at the CVT scanning position of the platen has integral transparent electrodes and incorporates a polymer/liquid crystal filler material that is white in a first state and transparent in a second state. A scanner is located on the scanner side of the platen. A controller is electrically connected to the electrodes. The controller controls the state of the polymer/liquid crystal filler material during scanning of a document and during white calibration of the scanner.