Hoffman Modulation Contrast Microscopy
Digital Image Gallery
The Molecular Expressions gallery of Hoffman modulation contrast photomicrography contains images taken under a wide variety of conditions using many different specimens. Use the links below to navigate to the individual entries in the gallery.
Ascorbic Acid (Vitamin C) - When combined with polarized illumination, Hoffman modulation contrast can produce colorful images that vividly illustrate phase differences in crystalline samples.
Basswood (tilia) Stem - Stained thin sections of plant tissue are often spectacular when photographed with Hoffman modulation contrast. This example of a Basswood stem illustrates the pseudo three-dimensional effect accompanying illumination with modulation contrast.
Biotin (Vitamin H) - Biotin forms spherulitic growth patterns when recrystallized in bulk from the melt. Photomicrographs of these crystallites form beautiful patterns when imaged with a combination of polarized light with a retardation plate and Hoffman modulation contrast.
Deer Tick (Ixodes dammini) - This menacing barbed mouth is used along with a specialized glue-like adhesive to attach the tick to its victim during feeding.
Diatoms - Diatoms are single-celled algae of the phylum Bacillariophyta and are found in all the Earth's oceans. One of the most prolific sea organisms, the nearly 16,000 species of this group form a significant portion of the aquatic food chain.
Duck-Billed Dinosaur (Hadrosaur) Bone - Using a combination of Hoffman modulation contrast and polarized light, this spectacular photomicrograph reveals mineral formation in Haversian canals.
Down Feathers - Vanes and barbs from the ubiquitous feather are highlighted in this photomicrograph prepared from a specimen illuminated with polarized light and Hoffman modulation contrast.
Fish Scales - Scales are a bony outgrowth of the skin of an animal, and are particularly common in fish, reptiles, and birds. Stained fish scales are good candidates for photomicrography with Hoffman modulation contrast illumination.
Adult Flea - Fleas are painful and irritating pests that infest many areas where the climate is warm and humid. We captured this adult flea on film using modulation contrast to enhance the photomicrograph.
Lanthanum Aluminate - Perovskites are a family of ceramic minerals that are closely related to many of the new high-temperature superconducting materials. Lanthanum aluminate is commonly used as a substrate for the thin-film deposition of these ceramic superconductors.
Liquid Crystalline DNA - DNA undergoes a series of liquid crystalline phase transitions when it is compressed in vivo into chromosome-sized packages. The photomicrograph presented in this section illustrates high molecular weight calf thymus DNA at concentrations approaching 650 milligrams/milliliter.
Llama Hair - Llama hair (or fur) is birefringent, making it a good candidate for observation with polarized light microscopy. When Hoffman modulation contrast illumination is used to supplement polarized light, the hair strands appear three-dimensional.
Mixed Pollen Grains - A mixture of stained pollen grains exhibits remarkable diversity in the contruction of these miniature gametes when viewed under the microscope using the Hoffman illumination technique.
Apollo 15 Moon Rock - Basalts consisting of volcanic lava were among the numerous rocks recovered from the surface of the moon by Apollo astronauts. This specimen reveals textural details of these rocks in thin section when photographed with modulation contrast and polarized light.
Petrified Wood - Thin sections cut and polished from petrified trees display a kaleidoscopic array of texture and color when visualized under Hoffman modulation contrast with polarized light.
Poly Benzimidazole - This high-tech polymer seems to acquire a three-dimensional neon-like appearance when photographed under a combination of Hoffman modulated contrast and polarized light with a first-order retardation plate in the light path.
Stentor (Trumpet-Shape) - This unique protozoan assumes many forms during the course of its daily activities, but the most interesting is the trumpet form acquired while feeding.
Tacrine (Cognex) - Beautiful crystallites of this important anti-Alzheimer's drug acquire a semi-three dimensional appearance when illuminated and photographed using a combination of polarized light and Hoffman modulation contrast.
Water Flea (Simocephalus) - This family includes the well-known Daphnia, but the species commonly found in Tallahassee is the larger Simocephalus. Water fleas are popular pond creatures for observation because of their compound eye and rapidly beating heart, which are readily viewed through their seemingly transparent shell (the refractive index approaches 1.5).
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