The designer must establish the architectural effect that is desired with the floodlighting. It is helpful to study the daylight effects on the building. This allows the designer to select the strong daylight effects that are desirable and to attempt to reproduce these effects under floodlighting. Daylighting effects are difficult to produce because of the directional characteristics of the sun and the diffuse characteristics of the sky. The sun is warm in color, while the diffused sky light is cool.
Shadows are never black but less bright and bluer.
Daylight is not constant but continually varying from day to day and hour to hour. The recommended illumination levels, E r , given in the IES Lighting Handbook 3 are recommended values that may vary depending on the design effects being created. Reflectance of the Building Surface material. The ambient illumination level of the area surrounding the building. The setback distance from the building and the specularity of the surface finish.