What is Light?

Light is energy! It is energy in the form of electro-magnetic radiation in waves.

The visible light spectrum spans from approximately 770nm to 380nm with the long wavelengths at the red end of the spectrum and the short wavelengths at the blue end.

From long to short wavelengths

           Fig. 1

White light has an even representation of all colours in the spectrum i.e. all wavelengths represents an equal amount of energy.


This spectrum is true for the sunlight but artificial light sources such as electrical lamps typically have a differently composed spectrum.


Standard light bulbs with incandescent (i.e. glowing) elements have a spectrum with a bias to the red end of the spectrum, while fluorescent lamps tend to have a very uneven spectrum with peaks in the green and blue areas of the spectrum. This therefore influences the perceived colours of any screen – or other object – we see.


The light we see is measured in a number of different ways and the following is the definition of the units relevant to displays:


Luminous intensity >



dnp denmark is the worldwide large-screen centre of Dai Nippon Printing Co. Ltd. With a 65 % market share, dnp is the world’s leading supplier of optical projection screens for high quality display solutions.

The dnp optical screen portfolio includes an extensive range of optical projection screens for both front and rear projection screen applications for all environments including home cinema / home theatre, meeting rooms / conference rooms, control rooms, signage & advertising and more.

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