Micrograph

100x light micrograph of Meissner's corpuscle at the tip of a dermal papillus.

40x micrograph of a canine rectum cross section.

A photomicrograph of a thin section of a limestone with ooids. The largest is approximately 1.2 mm in diameter.

Approximately 10x micrograph of an unusual coin.

A micrograph or photomicrograph is a photograph or similar image taken through a microscope or similar device to show a magnified image of an item. A microphotograph is a very small picture shown large like a real picture, e.g. a microdot. Microphotography is the production of such very small photographs. Two important applications of microphotography were the creation of computer chips and the creation of microdots to hide information. Written secret messages were embedded inside a dot the size of speck of dirt. Microdots were invented in the 1920s by Emanuel Goldberg.

To produce a photomicrograph, a camera may be affixed to a microscope in place of an eyepiece (direct projection setup) or the intermediate image is projected via a relay lens (also called projection eyepiece) onto the image sensor or film emulsion. A more complex arrangement requires the use of a relay lens behind a standard eyepiece to project the virtual image generated by the eyepiece onto the camera's recording surface. A prepared specimen is put under the microscope in the usual way and photographs taken. Alternatively, the image may be scanned and stored electronically and displayed on a screen and/or printed.

Micrographs are widely used in forensic engineering and forensic science, especially for recording trace evidence. It is also routinely used in scanning electron microscopy, often combined with energy-dispersive X-ray spectroscopy so that the area of the sample selected for analysis is directly visible.

Types

Photomicrograph

A light micrograph or photomicrograph is a micrograph prepared using a light microscope, a process referred to as photomicroscopy. At a basic level, photomicroscopy may be performed simply by hooking up a regular camera to a microscope, thereby enabling the user to take photographs at reasonably high magnification.

Photomicroscopists take photographs of many biologic subjects such as cells and proteins and insect eyes. Roman Vishniac was a pioneer in the field of photomicroscopy, specializing in the photography of living creatures in full motion. He also made major developments in light-interruption photography and color photomicroscopy. Nikon holds an annual contest each year called the International Small World Competition, which showcases exceptional photomicrographers.^[1]

Electron micrograph

An electron micrograph is a micrograph prepared using an electron microscope. However, the term electron micrograph is not used in electron microscopy. Common designation is a micrograph.

Digital micrograph

A digital microscope uses optics and a charge-coupled device (CCD) camera to output a digital image to a computer monitor. A digital microscope differs from an optical microscope in that there is no provision to observe the sample directly through an eyepiece. Since optical image is projected directly on the CCD camera, the entire system is designed for the monitor image.

Other uses

The technique is also used in making integrated circuits. The reverse of photomicrography where a large subject is rendered small is used in the production of microfilm and microfiche.^[2] With digital micrographs of calibration dots and special software it is possible to make extremely accurate measurements of objects in digital micrographs.

Gallery

• 

  Measurements of a large Colpodium at 400x.

• 

  Measurements of a large amoeba at 400x.

• 

  Snowflake micrograph by Wilson Bentley, 1890

See also

• Close-up
• Macrophotography
• Microscopy
• Digital microscope

References

1. ^ http://alum.mit.edu/pages/sliceofmit/2010/10/22/great-shots-of-a-small-world/
2. ^ Arnold, Rolls, and Stewart (1972). Applied Photography. London: Focal Press. pp. 213–230. 

External links

• Make a Micrograph – This presentation by the research department of Children's Hospital Boston shows how researchers create a three-color micrograph.
• Shots with a Microscope – a basic, comprehensive guide to microphotography
• Scientific microphotographs – free scientific quality microphotographs by Doc. RNDr. Josef Reischig, CSc.
• Micrographs of 18 natural fibres by the International Year of Natural Fibres 2009