For high illuminance requirements, e.g. for marking-out work and controls in metal processing at 750 lx, for colour inspections at 1.000 lx or for measuring instrument assembly work at 1.000 lx, it may be expedient – according to spatial dimension of the visual task area – to either have workstation-oriented general lighting or individual task lighting in addition to general lighting. In such cases, a sufficiently large surrounding area with appropriate illuminance must be provided. It is recommended to make this surrounding area as large as possible and to illuminate it with at least 500 lx to avoid adaptation issues when changing the viewing direction into the room (for the size of the surrounding area see fig.). The remaining surfaces in the room – especially the vertical surfaces of the field of vision – must be provided with lighting levels that ensure a balanced luminance distribution within the field of vision.