The optimal work light

For a long time it was considered sufficient to have a light on your desk. Good lighting was simply about things being visible, being able to see while you worked, read and wrote. But something happened in the middle of the 1990s. Suddenly there was a computer monitor on everyone’s desk. Computer monitors which reflected the light from fluorescent tube lighting and dazzled and strained our eyes. Then the T5 fluorescent lamp hit the market.

This solution became standard for Fagerhult

Fagerhult led the way for the energy efficient and ergonomic development of T5 luminaires, and we soon realised that a combination of direct and indirect light aimed up at the ceiling was preferable – from both a human and energy-saving point of view. 

This solution became standard for Fagerhult and generally accepted in the market. But we also wanted scientific proof. What is the most agreeable light distribution in a work situation? We started to research! 

Our aim was to find the best light distribution

The aim of the study was to determine the light distribution preferred by the people participating in the study – both as regards the visual task (visually) and their experience of the light in the room (emotionally).

The study was carried out in a room with no incidental daylight, solely artificial light from luminaires. The participants were positioned in four different places in the classroom where they carried out different work tasks. The luminance on the work desk (the calculation plane) was kept constant at 500 lux, a level in accordance with Swedish and European standards. The light distribution was changed four times to different levels of indirect light and direct light. 

This showed that a combination is best

The results showed that the light distribution the research subjects liked best comprised 56% indirect light and 44% direct light. This was equivalent to a wall luminosity of 78 cd/m2 and a ceiling luminosity of 128 cd/m2.  The study showed that the best working light is a combination of direct and indirect light which not only provides sufficient light levels on the work surface, but also creates ambient light by illuminating the walls and ceiling.

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