A densitometer is a

device A device is usually a constructed tool. Device may also refer to: Technology Computing * Device, a colloquial term encompassing desktops, laptops, tablets, smartphones, etc. * Device file, an interface of a device driver * Peripheral, any devi ...

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 A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.

. It determines the density of a sample placed between the light source and the

from differences in the readings. Modern densitometers have the same components, but also have electronic integrated circuitry for better reading.

Types

*Transmission densitometers that measure transparent materials *A transmission densitometer used to measure transparent surfaces measure color transparencies. Film & transparent substrates are some examples of common transparent surface measures. *Reflection densitometers that measure

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

reflected from a surface of any state.

Photography applications

Some are capable of both types of measurements selectable by a switch. They are used in film photography to measure densities of negatives with the switch in the "T" (Transmission) position and the saturation of a resulting print in the "R" position. Such measurements enable the photographer to choose the right photo paper and the correct exposure, obviating experiments with test strips. Once the papers and darkroom have been calibrated, the first print from a previously measured negative is a success at once.

Uses

*Densitometers are used for measuring color saturation by print professionals *Calibration of printing equipment *It serves as one of the Molecular tools for gene study, to quantify the radioactivity of a compound such as radiolabeled DNA. *They are also used for making adjustments so that outputs are consistent with the colors desired in the finished products. *They are used in industrial radiography to ensure x-ray films are within code-required density ranges. They are also used to compare relative material thicknesses. *Densitometers are used for process control of density dot gain, dot area & ink trapping. *Densitometer readings will be different for different types of printing process & substrates. *to find density of water * to find knowledge

References

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External links

In depth article explaining densitometers
Measuring instruments

Types

Photography applications

Uses

See also

References

External links