densitometer

(redirected from densitometers)
Also found in: Dictionary, Thesaurus, Medical.

densitometer

(den-să-tom -ĕ-ter) An instrument for measuring the density of exposure of a photographic emulsion. Densitometers have a light source and photocell to measure the transmission (or reflection) of the sample. They are used in obtaining quantitative measurements from photographic records of spectra, diffraction experiments, etc.

Densitometer

A photometer for measuring the optical density (the opposite of transmittance) of materials.

Densitometer

 

a device for measuring the optical density of developed photographic materials. They are classified according to the method of measurement (direct readout and the comparison principle), the type of light receiver (the eye, a photocell, or a photomultiplier), the type of output data (nonrecording devices and automatic recording devices), and the magnitude of the field being measured (densitometers proper, as compared with microdensitometers, which are sometimes referred to as microphotometers).

In devices with direct readout, a single light beam whose initial strength Φ0 is compared with the strength Φ of the beam after passage through a photosensitive layer is usually used. Devices whose operation is based on the comparison method have two light beams originating from the same source, one of which is the measuring beam and the other is the reference beam. In the most widely used type of photoelectric densitometer, the two beams are directed at two photoelectric receivers that are in a difference-reading circuit (that is, if the strength of the two beams is equal, the signal of the two receivers is zero) or are alternately connected to the same receiver. The difference signal, which is caused by unequal strength of the two beams, is brought to a zero reading with the aid of a variable light attenuator (for instance, a gray photometer wedge) inserted into one of the beams being compared and calibrated in units of optical density D = log Φ0/Φ.

The accuracy of densitometer measurements averages ±0.02 optical density units over the entire measurement range. For the best models the range is 5-6 density units; for relatively simple devices it is 2.5-3.0 density units (transmission coefficients of 10-5-10-6 and 0.003-0.001, respectively). The most typical densitometer models made in the USSR are the DFE-10 nonrecording wedge densitometer with selenium photocells (Dmax = 3.0) and the IFO-451 recording wedge microdensitometer with a photomultiplier, which is capable of measuring optical densities up to 2.5 units.

REFERENCE

Gorokhovskii, Iu. N., and T. M. Levenberg. Obshchaia sensitometriia: Teoriia i praktika. Moscow, 1963.

IU. N. GOROKHOVSKII

densitometer

[‚den·sə′täm·əd·ər]
(engineering)
An instrument which measures optical density by measuring the intensity of transmitted or reflected light; used to measure photographic density.

densitometer

i. An instrument for measuring the density or specific gravity of fuel. Also called a densimeter.
ii. An instrument for measuring the optical density (photographic transmission, photographic reflection, visual transmission, etc.) of a material, generally of a photographic image.

densitometer

A device that calibrates the relative strength of a color using complementary filters. Contrast with colorimeter.
References in periodicals archive ?
At Vale, a large global producer of iron ore, nickel and copper ore, radioactive densitometers have historically been used in the processing of ore slurries.
The global bone densitometers market report provides market size (Revenue USD Million 2013 to 2020), market share and forecasts growth trends (CAGR%, 2016 to 2020).
Global corporate-level profiles of key companies operating within the Asia-Pacific Bone Densitometers market category.
With a logical selection of densitometer type and range, correlation of film OD to exposure, measured with a radiometer-of-choice, can be achieved with simultaneous exposure.
Keep your densitometer free of dust and dirt and in a place where it won't be bumped or moved.
An upgrade for previous generations of Hologic's QDR series densitometers will be available in early 2005.
It is common understanding that the optical density of metallics cannot be measured with the same densitometers or spectro-densitometers used for conventional process colors.
The DexaCare(R) G4 is a "turn-key" table-top bone densitometer targeted at offices and private practices.
Using traditional single-point reading densitometers and charting statistics by hand would have required additional personnel at most facilities.
Ultimo claims that, prior to the emergence of the Ultimo device, nuclear densitometers were the only solution for noninvasive operations in the above applications.
com)-- Transparency Market Research "Bone Densitometers Market (DEXA, QCT, pDEXA, SEXA, pQCT, RA and QUS)- Global Industry Analysis, Size, Share, Growth, Trends and Forecast, 2013 - 2019," the global bone densitometers market was valued at USD 777.
Included in the toolkit are a series of downloadable MIF (Management Information Format) files designed to bring G7 support to the X-Rite 500 Series handheld densitometers and spectrophotometers.