optical density

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Related to optical densities: optical absorbance

optical density

The ability of a laboratory specimen to absorb or block the passage of light. The optical density of a laboratory sample can be used as an indicator of the concentration of specific components in the sample.
Synonym: optical absorbance
See also: density

optical density

a spectrophotometric measurement of light scattered by a suspension at a particular wavelength. Optical density measurements can be used to determine the BIOMASS concentration in a suspension, when, for instance, monitoring the GROWTH of a culture of MICROORGANISMS. It should be noted, however, that the microorganisms in the suspension will both scatter and, probably to a lesser extent, absorb the incident light, and it is the sum of these properties that is measured. It is therefore debatable what term should be applied. ABSORBANCE is sometimes used interchangeably with optical density, but this is not strictly correct. Optical density is generally accepted as the more appropriate term when measuring microbial growth.

density, optical

A term applied to optical filters. It is equal to the logarithm to the base 10 of the reciprocal of the transmission factor T thus,
where D is the symbol for optical density. Syn. absorbance. See absorbance; absorption; spectrophotometer; transmittance.
Table D1 Density of optical lens materials
ndensity (g/cm3)
glass
spectacle crown1.5232.54
dense barium crown1.6203.71
dense flint1.7063.20
dense barium flint1.7004.10
titanium oxide1.7012.99
plastics
PMMA1.4901.19
CR-391.4981.32
polycarbonate1.5861.2
cellulose acetate butyrate1.481.2
cellulose propionate1.461.2

Table D2 Relationship between optical density D and light transmission T of optical filters
DT (%)
0.0100
0.179.4
0.263.1
0.350.1
0.439.8
0.531.6
0.625.1
0.720.0
0.815.8
0.912.6
1.010.0
1.53.16
2.01.0
2.50.32
3.00.1
4.00.01
References in periodicals archive ?
As far during this stage the current and maximum total optical densities differ from those of the second component by [E.
The contrast determined according to ISO standards or other methods suggested by Boere and van Aken (1990), using only two optical densities (D2 and D1) on the characteristic curve divided by the difference between the log relative exposures (E2 and E1) that caused these densities, ignores the response between and above these values (Yakoumakis et al.
The film remained on the viewing box throughout the week, except when it was removed to measure the optical densities.
The fact that optical densities increased after incubation (amplification) for 24 and 48 hours suggested that there was a low level of contamination that was not detectable by optical densities at baseline.
We then normalized resultant optical densities to actin to control for differences in loading.
If the correlation is significant, then the wind tunnel drag for multirow barriers, barriers with rows with different optical densities, and barriers with variable spacing between the rows can be correlated with an expression of the equivalent optical density (EOD).
Speed index was taken to be 1 + base + fog (11) and contrast index was taken to be the difference in optical densities of the steps with minimum and maximum OD values that were not part of the toe or the shoulder, respectively.
To facilitate the comparison, the optical densities of phospho-ERK shown in Figure 1A and C are plotted with the SRE reporter activation shown in Figure 1B and D.
Thus, in the 2-yr period, data was obtained from these 16 windbarrier configurations: one, two, four, and eight rows of windbarriers having optical densities (per row) of 12.
Isolates were suspended in buffered saline, and solutions were adjusted in volume until optical densities (OD) were identical (1.
Another example of the excellent correlation between measured optical densities and AEC readings at both 80 kVp and 100 kVp is shown in Table 1.
Adjusted optical densities (OD) for each dilution were calculated by subtracting the [OD.