Your free myERCO account allows you to mark items, create product lists for your projects and request quotes. You also have continuous access to all ERCO media in the download area.


You have collected articles in your watchlist

Technical environment

Technical environment

Global standard 220V-240V/50Hz-60Hz
Standard for USA/Canada 120V/60Hz, 277V/60Hz
  • 中文

Our contents are shown to you in English. Product data is displayed for a technical region using USA/Canada 120V/60Hz, 277V/50Hz-60Hz.

Transmission: light passes through a medium


In physics, transmission refers to the passage of rays (light) through a medium. The measure for permeability is transmittance: this is the ratio of the transmitted luminous flux to the incident luminous flux. Similar to reflection, transmission can also be either directional or diffuse. Translucent materials are used in lighting technology to direct light, but also to model the spectrum.

Would you like to find out more?

How does transmission work?

In transmission, the light falling on a body passes through depending on the transmittance au of this body. The degree of scattering of the transmitted light plays a role. With perfectly transparent materials such as clear glass there is no scattering whatsoever. The light continues to penetrate the material in a directed manner. As the scattering power increases, the directional component of the transmitted light becomes increasingly smaller until, in the case of complete scattering, only diffuse light is emitted. When transmitted through frosted glass, directional light becomes diffuse. The light scatters many times due to multiple reflection and a uniform distribution of brightness is achieved.

Transmitting materials in luminaires can be transparent. This applies to simple cover glasses as well as to filters which absorb specific spectral ranges but transmit the others, thus creating colored light or lowering the UV or infrared component. Occasionally, diffusing materials – for example opal glass or opal plastics – are also used as luminaire covers to avoid the effects of glare by lowering the lamp luminance.

Would you like to find out more?

Further topics on optics

Do you need further information?

You can contact your regional contact partner via:

You can gladly send us an e-mail or ask your question here

Your data will be handled confidentially. For further information see Data protection declaration.




Planning light

About ERCO