Eyewear is rated for optical density ( OD ), which is the base-10 logarithm of the attenuation factor by which the optical filter reduces beam power.
32.
The star's stellar winds are strong, at, but slow, and have been measured on the order of 100 km / s which contributes to their optical density.
33.
Lenses of fixed tint are graded according to the optical density of the tint; in the UK sunglasses must be labelled and show the filter category number.
34.
The observable radiation originates from a pseudo-photosphere where the optical density of the wind drops to near zero, typically measured at a particular Rossland opacity value such as.
35.
More sophisticated techniques will show proportional differences in optical density . "'Phase contrast "'is a widely used technique that shows differences in refractive index as difference in contrast.
36.
This technology combines an out-of-band rejection of <-60 dB and an optical density higher than OD 6 with a tunability over the near infrared regions of the electromagnetic spectrum.
37.
The optical density of the HS band is proportional to the ? HS, and a ? HS vs . temperature can be plotted as in "'Figure 10 " '.
38.
(where i is optical density of exposed photographic emulsion, a function of I, the intensity of the source being observed, and t, the exposure time, with p a constant ).
39.
The reciprocal relationship is assumed in most sensitometry, for example when measuring a Hurter and Driffield curve ( optical density versus logarithm of total exposure ) for a photographic emulsion.
40.
Areas of the emulsion receiving larger amounts of light ( reflected from a subject being photographed, for example ) undergo the greatest development and therefore results in the highest optical density.
