Vertical light: recognising people and information
Lighting quality extends beyond the floor. Faces, boards and shelving need light on their own surfaces.
A horizontal calculation plane can represent a desk or floor. Faces, shelf fronts and signs need assessment on vertical surfaces instead. Cylindrical illuminance considers light arriving around a vertical axis and can support evaluation of spaces used for face-to-face communication.
Light coming only from above may leave eye areas in shadow. Appropriate lateral light and brighter room surfaces can improve recognition. Completely flat lighting is not always desirable either: some modelling helps faces and objects retain a readable shape.
Define what people need to see, from which direction and at what height. Reception desks, classrooms and meeting rooms consequently require different assessment planes from circulation routes. Target values should follow the actual use and applicable requirements, rather than applying one universal lux figure to every space.
What to clarify for your project
- List faces, labels and presentation surfaces.
- Define viewing directions and heights.
- Review shadows alongside glare.
Remember: Identify the relevant viewing surface before comparing illuminance figures.