Transparency and translucency: Difference between revisions

Revision as of 14:37, 7 January 2025

Revision as of 12:15, 5 March 2025

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[[File:Dichroic filters.jpg|thumb|right|[[Dichroic filter]]s are created using optically transparent materials.]]

In the field of [[optics]], '''transparency''' (also called '''pellucidity''' or '''diaphaneity''') is the [[physical property]] of allowing [[light]] to pass through the material without appreciable [[light scattering by particles|scattering of light]]. On a [[macroscopic scale]] (one in which the dimensions are much larger than the wavelengths of the [[photon]]s in question), the photons can be said to follow [[Snell's law]]. '''Translucency''' (also called '''translucence''' or '''translucidity''') allowsis the physical property of allowing light to pass through butthe doesmaterial not(with necessarilyor (again,without onscattering of light). It allows light to pass through but the macroscopiclight scale)does not necessarily follow Snell's law on the macroscopic scale; the photons canmay be scattered at either of the two interfaces, or internally, where there is a change in the index of [[refraction]]. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction.<ref>{{cite journal |last=Thomas |first=S. M. |title=What determines whether a substance is transparent? |journal=[[Scientific American]] |date=October 21, 1999}}</ref> Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant [[spectrum]] of every color. The opposite property of translucency is [[Opacity (optics)|opacity]]. Other categories of visual appearance, related to the perception of regular or diffuse reflection and transmission of light, have been organized under the concept of [[Cesia (visual appearance)|cesia]] in an order system with three variables, including transparency, translucency and opacity among the involved aspects.

When light encounters a material, it can interact with it in several different ways. These interactions depend on the [[wavelength]] of the light and the nature of the material. Photons interact with an object by some combination of reflection, absorption and transmission.

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Transparency can provide almost perfect [[camouflage]] for animals <!--or possibly military equipment?--> able to achieve it. This is easier in dimly-lit or turbid [[sea]]water than in good illumination. Many [[marine biology|marine animals]] such as [[jellyfish]] are highly transparent.

[[File:Opacity Translucency Transparency.svg|thumb|250px|right|Comparisons of 1. opacity, 2. translucency with scattering, and 3. transparency; behind each panel (from top to bottom: grey, red, white) is a star.]]

== Etymology ==