Definition

In PHOTOGRAPHY, a measure of the degree of blackening of an exposed film, PLATE or paper after development, or the direct IMAGE (in the case of a print-out material). It is defined strictly as the logarithm of the optical OPACITY. In OCEANOGRAPHY, density is equivalent to SPECIFIC GRAVITY and represents the ratio, at ATMOSPHERIC PRESSURE, of the WEIGHT of a given volume of SEA WATER to that of an equal volume of distilled water at 4.0°C.