Looking in and looking out

The ratio of the luminance levels in front of and behind the pane of glass determines how easily one can see through the window. Inclined glass surfaces require additional analysis to minimise the reflections caused by light. When it comes to fabric materials, their degree of transparency is dictated not only by their transmission factor but also by their colour and the lighting situation. The lighting in this boardroom uses spotlights, wallwashers and even indirect luminaires, with the trees outside being illuminated by projectors.

Looking out

Brightly lit surfaces can result in reflections on the facade when looking out at night. To improve the situation, it is recommended to minimise the lighting on the wall surfaces and to limit it to a few areas. Luminaires that are visible in the room and that not only illuminate but are illuminated can cause disturbing reflections. On the other hand, luminaires that are recessed in the ceiling or are otherwise shielded will avoid bright reflections on the facade. Due to higher daytime luminance, the problem of reflections when looking out does not arise.

Outwardly inclined glass surface

If the facade is tilted outwards, it is necessary to avoid a high luminance on the ceiling as this can otherwise result in unpleasant reflections on the glass. This luminance can be due to luminaires on the ceiling or from the illuminated area of the ceiling. Bright decorative luminaires that cause dazzling reflections in the facade are particularly problematic. Narrow-beam luminaires with high cut-off angles not only ensure good visual comfort inside the room but also when looking outside. The lighting concept shown here, using a suspended light structure to provide the ceiling lighting, demonstrates the disturbing reflections on the facade and the obscured view outside.

Inwardly inclined glass surface

Inwardly angled facades can reflect the floor when viewing outside. A lighting concept with a high illuminance level close to the window on the floor or furniture may well result in annoying reflections obscuring the view outside. In such cases, the ambient lighting can be provided by way of indirect lighting on the ceiling resulting in no reflection on the inwardly inclined glass surface. Whereas, lighting the floor or the tables causes bright reflections in the glass facade, impairing the view to the outside.

Looking in: With indoor lighting

To provide a good view into a building, it is recommended to have a lighting concept with a higher interior than exterior luminance. Indoor lighting reveals the depth of the room behind the facade with vertical lighting contributing to the creation of a clear image of the room. If the outdoor lighting is limited, there will be less reflection of the surroundings, making it easier to see inside.

Looking in: Without indoor lighting

If there is no internal lighting, then the glass will act as a mirror of the outer surroundings.

Facades with fabrics: gauze lit

If there is gauze material in front of the facade, then the ratio of the brightness on the gauze and the brightness of the space beyond will determine whether it is possible to see though the gauze. If the background is dark and the gauze is illuminated, the gauze will appear opaque.

Facades with fabrics: gauze unlit

If there is gauze material in front of the facade, then the ratio of the brightness on the gauze and the brightness of the space beyond will determine whether it is possible to see though the gauze. If the gauze is unlit and lighting is used in the background, the gauze will appear more transparent making it possible to see out of the room.

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