Microdensitometer on:
[Wikipedia]
[Google]
[Amazon]
A microdensitometer is an optical instrument used to measure optical densities in the microscopic domain. J. C. Dainty and R. Shaw, ''Image Science'' (Academic, New york, 1974).T. H. James, ''The Theory of the Photographic Process'' (Eastman Kodak, Rochester, 1977). F. J. Duarte, ''Tunable Laser Optics'' (Elsevier Academic, New York, 2003) Chapter 10. A well-known microdensitometer, used in the photographic industry, is a granularity instrument or granularity machine. The
A microdensitometer is an optical instrument used to measure optical densities in the microscopic domain. J. C. Dainty and R. Shaw, ''Image Science'' (Academic, New york, 1974).T. H. James, ''The Theory of the Photographic Process'' (Eastman Kodak, Rochester, 1977). F. J. Duarte, ''Tunable Laser Optics'' (Elsevier Academic, New York, 2003) Chapter 10. A well-known microdensitometer, used in the photographic industry, is a granularity instrument or granularity machine. The granularity
Granularity (also called graininess), the condition of existing in granules or grains, refers to the extent to which a material or system is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is subd ...
measurement involves the use of an optical aperture, 10-50 micrometers in diameter, and in the recording of thousands of optical density readings. The standard deviation of this series of measurements is known as the ''granularity'' of the measured transmission surface, optical film, or photographic film
Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin photographic emulsion, emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of th ...
, in particular .
An alternative version to the traditional point-by-point microdensitometer is the beam expanded laser microdensitometer.F. J. Duarte, Electro-optical interferometric microdensitometer system, US Patent 5255069 (1993). This instrument can illuminate simultaneously an area a few centimeters wide with an ultra thin height, in the micrometer regime. Advantages include increased depth of focus, significant increases in data collection speed, and superior signal to noise ratios. In microscopy applications, this type of ultra thin beam-expanded illumination can also be known as light sheet illumination or selective plane illumination.
This measurement technique, using ultra-thin expanded laser beams, is particularly useful to detect microscopic imperfections in optical coatings or transmission optical surfaces.F. J. Duarte, ''Tunable Laser Applications'' (CRC, New York, 2009) Chapter 12.
See also
*Densitometer
A densitometer is a device that measures the degree of darkness (the optical density) of a photographic or semitransparent material or of a reflecting surface. The densitometer is basically a light source aimed at a photoelectric cell. It determ ...
* Microscopy
* N-slit interferometer
The ''N''-slit interferometer is an extension of the double-slit experiment, double-slit interferometer also known as Young's double-slit interferometer. One of the first known uses of ''N''-slit arrays in optics was illustrated by Isaac Newton, Ne ...
* Particle size
Particle size is a notion introduced for comparing dimensions of solid particles ('' flecks''), liquid particles ('' droplets''), or gaseous particles ('' bubbles''). The notion of particle size applies to particles in colloids, in ecology, in ...
References
{{reflist Optical metrology Microscopy Measuring instruments