Hoffman Modulation Contrast Microscopy
Hoffman modulation contrast is an oblique illumination technique that enhances contrast in both stained and unstrained specimens by detection of optical phase gradients. This section includes discussions of transmitted and reflected light applications using Hoffman modulation contrast and links to interactive Java tutorials designed to aid in understanding the technique. Also included are virtual microscopes and an image gallery of photomicrographs made using modulation contrast either alone or in combination with other illumination mechanisms.
The featured section serves as an introduction to the basic concepts in modulation contrast microscopy with numerous illustrations and examples of how the technique is implemented.
Problems with proper slit alignment between the condenser and the objective modulator are the most common source of errors with modulation contrast microscopy.
Explore this simulated virtual microscope that provides several examples of specimens in optical section while passing through focus using modulation contrast illumination in this interactive tutorial.
Aligning the condenser slit with the objective modulator plate is one of the most critical aspects of microscope configuration for Hoffman modulation contrast. Practice this simple, yet often misunderstood, alignment technique.
Students can discover how rotation of the substage polarizing filter affects image contrast in Hoffman modulation contrast microscopy in this interactive java tutorials.
Digital Image Gallery
Modulation contrast illumination produces a pseudo three-dimensional effect that can be used in combination with other illumination techniques to achieve spectacular images.