Good lighting in workplaces is essential for office workers’ safety. The key factors to consider when determining the adequacy of lighting are:

Amount of light in an area

Number, type and position of the light sources, and

Tasks or activities, and how often and for how long these are performed.

Level of light

We are able to see quite well in a wide range of lighting levels as the eye can adapt to different lighting conditions. But to reduce the need to adapt when changing tasks or moving from one work area to another, specific levels of lighting are recommended. The amount of light falling on a surface is known as the illuminance of that surface and is measured in lux.

Quality

This refers not only to the level of lighting but also to other factors that include:

The number and type of lights in use (fluorescent tubes, tungsten and halogen lights)

Type of light fittings used

Position of the lights

How colours appear under them, and

Maintenance of the lighting system

Glare in a work area

This occurs when one part of an area is much brighter than the background or vice- versa. For example, when a bright window is positioned behind a computer screen. This may cause eye fatigue and headaches and make it difficult to see the screen. There are several ways to reduce glare in the office environment:

Control light from windows with, for instance, venetian blinds

Reduce the contrast between the foreground and background. For example, off-white paper reduces the contrast between the paper and print

Reposition the workstation to reduce the light falling on the work surface

Reduce the general lighting.

Reflections

Light reflected from a work surface can make it difficult to see what is on it. To assess reflections, holding a sheet of paper over a VDU screen or placing a mirror over the work surface can help reveal the source of the reflections.

Reflections from computer screens have been reduced by the development of colour monitors and non-reflective screens. Additional controls for reflections include positioning the screen side-on to the main light source.

Shadows

Shadows can reduce the visibility of work, contribute to glare problems and cause the adoption of poor posture while working. Holding a piece of paper above the work surface can indicate whether shadows fall over it. The effect of shadows can be assessed by observing a person’s posture.

Re-positioning work or redirecting lighting are the two main ways of reducing shadows. Barriers to light falling on the work surface, such as an overhead shelf, should be removed. An adjustable lamp may be a great solution.

Posture

When people find it difficult to see what they are working with, it is common for them to lean closer to the object or to bring it closer to their eyes. In both cases, this may lead to an awkward posture. If lighting is contributing to poor posture, consider the following:

Is a shadow being cast over the work surface?

Is there enough light for the task being performed?

Are reflections or glare causing the unsatisfactory posture?

Visual rest

A visual rest location such as a view out of a window or a picture at a distance can provide exercise to other eye muscles while resting the tired ones.

Colour

Choice of colours can determine the mood of an environment and the level of reflection from a surface. It is recommended that ceilings have high reflectance (reflecting around 80 per cent of the light), and they be usually white or off-white. Walls should have 50-70 per cent reflectance (subdued colours) and gloss or semi-gloss finish. Floors should have low (less than 20 per cent reflectance) and therefore, should be darker and not glossy.

(The author is an interior design consultant, specialising in the design of corporate and residential interiors. As a senior faculty member at a Calcutta institute, she has delivered lectures, guided research and conducted projects in the field of ‘Housing & Interior Design’ for over two decades. She can be contacted at kusumsmail@yahoo.com)