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What is direct lighting, semi direct lighting, semi indirect lighting ?


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What do you mean by direct lighting?

In this lighting scheme the light does not reach the surface directly from the source, maximum light is thrown upwards to the ceiling from which it is distributed all over the room by diffused reflection. The glare being reduced the resulting illumination becomes softer. It is used for decoration purposes in cinemas, theaters, and hotels etc. and in workshops where large machines and other obstructions would cause troublesome shadows if direct lighting is employed.

What do you mean by semi-direct lighting?

In this lighting scheme the total light flux is made to fall downwards directly with the help of semi-direct reflector on the working surface and also to illuminate the ceilings and walls. It is best suited to rooms with high ceilings where a high level of uniformly distributed illumination is desirable.

What do you mean semi-indirect lighting?

In this lighting scheme the light comes partly from the ceiling by diffused reflection and party direct from the source on the working surface. As it is glare free with soft shadows it is mainly used for indoor light decoration purposes.

What do you mean by general lighting?

In this lighting scheme lamps made of diffusing glass are employed which give almost equal distribution of light in all direction.

What do you mean by local lighting?

Local lighting means an intense illumination on some particular points by means of adjustable fittings. In this lighting scheme lamps are mounted in deep reflectors to avoid glare.

What do you mean by specular reflection and diffuse reflection?

Specular reflection means the reflection on some in the form of a beam of light but not scattered. In this reflection, unless the eye is placed in the path of the reflected beam the viewer is unaware of the existence of light.
Diffuse reflection means the reflection of light energy in the scattered form in all direction. In this reflection, the viewer can see the illuminated surface but not the light source.


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