Quality features in lighting

Like occupational and recreational activities such as reading a book, assembling miniature electronice components,doing techinial drawings,running colour checks in a printing works etc. visual tasks vary in their requirments.

These visual task determine the demands to be made on the lighting system.
Careful planning and execution are prerequisites for artificial lighting of good good quality .Here is what specific "quality features"determine:-

• the lighting level- the brightness
• glare limitation - undisturbed vision with neither direct nor refleted glare.
• harmonious distribution of brightness- an even balance of luminance.(brightness)
• the light colour - the color appearance of lamps, and in combination with
• colour rendering- the correct recognition and differentiation of colours, and room ambience,
• the direction of light and
• modelling - the recognition of three-dimensional forms and surface textures

Depending on the use and appearance of a room, these "quality features" an be given differing weightings, The stress maybe on :

• visual performance by adjusting the lighting level and glare limitation,
• visual comfort by colour rendering and harmonious brightness distribution,
• the visual ambiance by selection of light colour, lighting direction and modelling.