What Is a Wallwasher? Wallwashing Lighting and Choosing Luminaires
Short answer
A wallwasher is a luminaire whose asymmetric optic spreads light evenly over a wall surface from top to bottom. The aim is to light the wall uniformly without patches; if the goal is to bring out texture, grazing light, with the luminaire placed very close to the wall, is preferred.
What makes a space feel bright is often not the light falling on the floor but the light falling on the walls. The eye perceives vertical surfaces; a room with lit walls looks more spacious than a room with the same lux level but dark walls. Wallwasher luminaires are designed to create this effect in a controlled way.
How does a wallwasher work?
What sets a wallwasher apart is its asymmetric optic. An ordinary spotlight distributes light symmetrically downwards and around it; placed close to a wall, it leaves a bright scallop on the upper part of the wall. A wallwasher directs most of the light onto the wall and spreads it from the top of the surface to the bottom. Lined up at the right spacing, it creates continuous, patch-free illumination along the wall.
Wallwashing versus grazing
| Wallwashing | Grazing | |
|---|---|---|
| Luminaire position | At a certain distance from the wall | Very close to the wall |
| Angle of incidence | Steeper to the surface | Very shallow to the surface |
| Result | An even, flat appearance | Texture, joints and shadows emphasised |
| Suitable surface | Render, paint, smooth surfaces | Stone, brick, timber, textured surfaces |
On a smooth wall, grazing light also emphasises small imperfections; on a textured stone wall, wallwashing flattens the texture. The choice must be made according to the surface.
Where is it used?
- Façades: Even lighting of building surfaces at night.
- Lobbies and galleries: A soft, even background for walls and artworks.
- Shops: Lighting shelf walls; products stand out from the background.
- Meeting rooms and offices: Wall brightness increases visual comfort and makes the space look more open.
Selection and layout
- Distance: As a starting value, about one third of the wall height; the exact value by calculation.
- Spacing: The spacing between luminaires is usually kept close to the distance from the wall; checked with software for a patch-free result.
- Colour: 3000K–4000K depending on the wall colour and material; CRI 80 or higher, 90 or higher for artworks.
- Protection: IP65 or higher outdoors, IP67 for in-ground models.
Conclusion
A wallwasher is the most reliable way to light a wall evenly without patches; when the aim is to bring out texture, it gives way to grazing light. To determine the right technique and layout for your façade and interior projects, you can use our lighting design service.
Frequently Asked Questions
What is the difference between wallwashing and grazing?
A wallwasher stands at a certain distance from the wall and lights the surface evenly; a grazing luminaire stands very close to the wall and skims light across the surface, emphasising texture and shadows.
How far from the wall should a wallwasher be placed?
As a general starting value, at about one third of the wall height; the exact distance and luminaire spacing are determined by calculation according to the luminaire's light distribution.
Are wallwashers used indoors?
Yes. Lighting the walls in lobbies, galleries, shops and meeting rooms makes the space look more open; outdoors they are used for façade lighting.
What IP rating should a wallwasher have?
IP20 may be enough indoors; on exterior façades at least IP65, and IP67 for in-ground models.