Posts that relate to the Keyword: Köhler

Human hair under the microscope

Today I’d like to show you a nice microscopic picture, which I took several years ago of two human hair. The pictures on the right show you the original, unprocessed image at the top, and a second cleaned-up image with a nice background on the bottom. The top image shows darkened corers from the field [...]

Köhler illumination to reduce reflections

The Köhler (or Koehler or Kohler) field diaphragm is located above the light source. It is responsible for controlling the width of the light beam (but not its intensity). The light source of a microscope without Köhler illumination will illuminate the whole specimen, which may be the source of stray light and excessive heating of [...]

Adjusting Koehler Illumination

Koehler illumination ensures that the specimen receives a bright uniform light. Only those areas actually seen are illuminated.

Advantages of Koehler Illumination

Koehler illumination offers a range of advantages over “critical illumination”. Illumination is more uniform, specimen heating is reduced as well as light reflections for photographic work.