There is a tendency to give less attention to the daylighting of rooms in modern buildings than to a combination of day lighting and electric lighting. The integration of daylighting with electric lighting is particularly suitable in deep rooms and provides greater freedom of planning by reducing the dependence on windows for ordinary working illumination. This form of interior lighting which is known as PSALI (Permanent Supplementary Artificial Lighting of Interiors) will give the appearance of a daylit room even when most of the working surfaces receive light from artificial sources. Window areas with this method of lighting may be reduced to about one-sixteenth of the floor area, which will provide sufficient light near the windows and a view of the outside.