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a branch of photographic sensitometry devoted to measurements of the absorption and scattering of light by developed photographic layers.

The methods of densitometry make possible the quantitative evaluation of the final photographic effect based on the optical density of blackening in the photosensitive layer. There is a nearly linear relationship between the surface concentration of silver in the blackened area and the optical density; their ratio is called the photometric equivalent of blackening. The optical density increases with the degree of dispersion of the silver in the blackened area. Correspondingly, the extent of the optical usefulness of the silver in the blackened area increases with the disperseness of the silver halide in the original light-sensitive layer and with the relative magnitude of the exposure of this layer to light. Because of the nonhomogeneous nature of the blackened areas, the light absorption in these areas is accompanied by strong diffusion. Therefore, the magnitude of optical density depends on the geometric structure (aperture) of the light beams that are incident on the blackened area and are directed to a receiver after passing through the blackened area.

A distinction is made between regular density (D ║) and integral density (DE), which are measured upon illumination of the blackened area by a beam of parallel light rays and upon reception, in the first case, of only that part of the light beam that has not changed direction during passage through the blackened area and, in the second case, of the entire light beam. In addition, diffuse density (D#), which is measured using an ideally diffuse beam of light to illuminate the blackened area, and effective density (D ψ), which is measured under intermediate conditions encountered in practice, are also distinguished. The difference D ║ -DE is a measure of the light diffusion in blackened areas. The diffuse density is commonly used in sensitometry.

The optical density of blackening is measured using densitometers and microphotometers.

The measurement of color fields in developed materials for color photography constitutes a special branch of densitometry.

References in periodicals archive ?
TechNavio's report, the Global Bone Densitometry Market 2014-2018, has been prepared based on an in-depth market analysis with inputs from industry experts.
However, the high costs of digital mammography systems and axial DEXA bone densitometry systems will deter market expansion.
The 4,236 primary care physicians who participated in the study took bone densitometry measurements of the women in one of four ways: x-ray measurements at the heel, forearm, or finger, or ultrasound measurement of the heel.
The Medicare Bone Mass Measurement Coverage Standardization Act of 1998 widened the Medicare indications for bone densitometry so that more women can have the test every 2 years without having to pay for it.
Bone densitometry has proven cost-effective for assessing the risk of osteoporosis in women who are at or near the age of eligibility for Medicare benefits.
Solis will implement full field digital mammography and continue to offer breast ultrasound, bone densitometry, and general ultrasound at the Women's Imaging Center location.
Bone densitometry has "revolutionized the understanding and prevention of osteoporosis," but it has also confused osteoporosis treatment and monitoring, Dr.
COLORADO SPRINGS - Peripheral bone densitometry is a problematic and overused test, Dr.
In this research, Frost & Sullivan's expert analysts thoroughly examine the following markets: mammography systems and bone densitometry systems.
In addition to digital screening, digital diagnostic mammography and computer-aided detection, Solis will offer breast ultrasound, bone densitometry and stereotactic and ultrasound-guided biopsy.
ARA offers a complete range of services including routine x-rays, fluoroscopy, digital mammography and women's imaging services, ultrasound, CT, MRI, neuroradiology, myelography, pediatric radiology, interventional radiology, neurointerventional radiology, nuclear medicine, PET/CT, and bone densitometry.