This interactive tutorial explores how rotation of the substage polarizing filter affects image contrast in Hoffman modulation contrast microscopy. Instructions for operation of the tutorial appear below the applet window.

	Interactive Java Tutorial
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The tutorial initializes with a specimen randomly selected from the pull-down Choose a Specimen menu. Positions of the three sliders are also randomized when the tutorial is first launched or when a new specimen is selected. Use the Polarizer Rotation slider to simulate rotation of the substage polarizer to increase or decrease specimen contrast. The Brightness slider simulates microscope lamp illumination intensity and may be used to control specimen brightness. A Contrast slider is used to simulate varying degrees of polarizer extinction to adjust the amount of contrast observed in the specimen.