density
(den′sit-ē)

[L. densitas, thickness]
1. The relative weight of a substance compared with a reference standard; a physical parameter of a substance that is equal to its mass per unit volume.
SEE: specific gravity
2. The quality of being dense; a physical parameter of a substance that is equal to its mass per unit volume.
3. The extent of exposure of image receptors; formerly known as the blackness of the metallic silver that was visible in a developed radiographic film image.
4. In digital imaging, density has been replaced by image receptor (IR) exposure.
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