Without light, objects are not visible; without shadow, they are only two-dimensional images. The interaction of light and shadow is vital for producing the depth needed for good recognition of shapes, surfaces and structures. At the same time, the right mix of directional light and modelling makes for visual comfort and an agreeable lighting atmosphere.

Direction of light is responsible for modelling. It is determined by the beam characteristics of luminaires and their positioning in the room.

The ideal solution: a combination of diffuse and directional light

A bright room with only diffuse lighting and no modelling makes a monotonous, uncomfortable impression: objects and distances are hard to recognise and orientation is difficult.

By contrast, punctual light sources delivering extremely directional light form deep, sharp edged shadows in which nearly nothing can be made out. At the same time, dangerous optical illusions may be created, e.g. when using tools or ascending stairs.

According to DIN EN 12464-1, ideal modelling – soft-edged shadows – is achieved with a balanced mix of directional and diffuse lighting. Diffuse lighting can be provided by e.g. luminaires with an indirect lighting component while directional light can be delivered by downlights or direct louver luminaires for the office.