Ambient lighting is the term given to the uniform illumination (Uniformity) of an interior designed to create roughly equal visual conditions throughout. This is mostly achieved with a regular luminaire configuration, e.g. ceiling lighting systems.
For many applications (i.e. types of interior or activity involved) the required level of Illuminance is defined in the standards with reference to the working plane (EN 12464, ÖNorm 1040, SEV 8912).
In addition to an adequate level of illuminance, however, other criteria for a good lighting system apply (Ten Guidelines for Right Light).