Objects can be illuminated with light directed from between 30° to 45° to the vertical. The steeper the incident light, the more pronounced the three-dimensionality of the illuminated object. If the angle of incidence of the light is approximately 30°, the so-called "museum angle", this produces maximum vertical lighting and avoids reflected glare that may disturb the observer. In the case of reflecting surfaces, e.g. oil paintings or pictures framed behind glass, attention must be paid to the angle of incidence of the light to avoid disturbing reflections that may arise in the observer's field of vision. This will also avoid any heavy shadow, e.g. picture frame shadows on the picture.