The Definition of Optical Density and the Measurement

From:Linshang     Time:2018/5/12 17:31:43     Browse:
Optical density is the natural logarithm of the ratio of incident to transmitted radiant power through a material. For measuring the optical density of some materials, you can use Linshang LS117 Optical Density Meter.

       In chemistry, absorbance or decadic absorbance is the common logarithm of the ratio of incident to transmitted radiant power through a material, and spectral absorbance or spectral decadic absorbance is the common logarithm of the ratio of incident to transmitted spectral radiant power through a material. Absorbance is dimensionless, and in particular is not a length, though it is a monotonically increasing function of path length, and approaches zero as the path length approaches zero. The use of the term "optical density" for absorbance is discouraged.In physics, a closely related quantity called "optical depth" is used instead of absorbance: the natural logarithm of the ratio of incident to transmitted radiant power through a material. The optical depth equals the absorbance times ln(10).


       The term absorption refers to the physical process of absorbing light, while absorbance does not always measure absorption: it measures attenuation (of transmitted radiant power). Attenuation can be caused by absorption, but also reflection, scattering, and other physical processes. 
       Linshang
LS117 Optical Density Meter has three measurement mode:
       1.ABS mode (Measuring mode for transmittance and absolute optical density).
       2.COM mode (Measuring mode for relative optical density).
       3.DOT mode (Measuring mode for dot area). 


       Linshang
LS117 Optical Density Meter can be used to test the following materials:
       1.Film rolls
       2.X ray films and aluminum laminated films
       3.Milky,frosted materials.For example,Decorative glass or frosted glass, ceiling lamp cover and other materials.


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