In short
- Grazing places the light source very close to the wall so light skims across it. Every ridge catches light and every hollow throws a shadow.
- Distance from the wall is the main control. Closer gives more drama and a brighter band at the base; further gives a softer, more even graze.
- Laterite, sandstone and rough stone reward grazing. Smooth plaster punishes it by revealing every defect.
What grazing does
Washing lights a wall evenly from a distance and flattens texture. Grazing lights it from a sharp angle and exaggerates texture. On a laterite or stone facade, grazing turns the material into the design.
The night image of the whole building, and how grazing fits into it, is covered in The Night Image.
The geometry
- Setback: the distance from the light to the wall face. For grazing, typically 100–300 mm (convention). Below 100 mm, the base becomes a hot band; above 300–400 mm, grazing turns into washing.
- Beam: narrow in the vertical plane so light travels up the wall. Asymmetric or elliptical optics spread light along the wall while keeping it close.
- Spacing: for point sources, spacing similar to the setback to a little more avoids scallops at the base. Linear grazers avoid scallops altogether.
- Height reached: a narrow beam reaches higher. Tall facades need narrow optics, more output, or lighting from both base and top.
Uplight or downlight?
| Direction | Effect | Consider |
|---|---|---|
| From below (in-ground or base) | Dramatic, theatrical, strong texture | Glare to passers-by, water and debris in in-ground fittings |
| From above (parapet or soffit) | Natural, like moonlight; less glare | Fitting must be concealed at the top; less upward spill |
| Both | Even graze on tall walls | Two sets of fittings to conceal and maintain |
Downward grazing from the parapet also reduces light into the sky. See Light Spill and Dark Skies.
Materials
Laterite
- Odisha’s characteristic red-brown, porous stone is ideal for grazing. Its pits and ridges produce deep shadows.
- Warm colour temperature (2700–3000 K) and good red rendering bring out its colour. Cool light turns it grey-brown. See Beyond Ra.
- Laterite weathers and darkens; a facade lit at handover may need more output after a few monsoons.
Sandstone and dressed stone
- Grazing shows coursing and tooling. Even, consistent setback is critical; any variation shows as uneven bands.
- Lighter stones reflect more and need less output.
Rough-cut and split stone
- Very deep shadows. Can look heavy if overlit; use lower output than you expect.
Plaster and concrete
- Grazing reveals trowel marks, joints and undulations. Use it only where the finish is intended to be seen, or choose washing instead.
Detailing
- Conceal the fitting. A recessed channel in the plinth, a slot in the paving, or a parapet coping with a lip.
- Drainage. In-ground and channel fittings flood in the monsoon. Provide a gravel bed and drainage below, and specify suitable ingress protection. See Coastal Exterior Lighting.
- Windows. Grazing past windows lights interiors and creates glare. Stop or shield the graze at openings.
- Corners and ends. Decide whether the graze turns the corner or stops; a graze that fades out mid-wall looks unfinished.
- Mock-up. Grazing depends on the actual stone and the actual setback. Test on site on a sample panel at night.
Control
- Facade grazing usually runs on an astronomical clock with an evening scene and a reduced or off late-night scene.
- Dimming lets you tune intensity on site after the stone has weathered.
Specification notes
- Set the setback (typically 100–300 mm) and keep it consistent along the wall.
- Choose narrow or asymmetric optics by facade height; use linear grazers where scallops would show.
- Specify 2700–3000 K and good red rendering for laterite and warm stone.
- Detail concealment, drainage and ingress protection for every fitting.
- Stop or shield the graze at windows.
- Mock up on site with real stone at night before approval.
Frequently asked questions
How far from the wall should grazing lights be?
Typically 100–300 mm. Closer creates more drama and a brighter base; further gives a softer effect. Beyond about 400 mm, the effect becomes washing rather than grazing.
What colour temperature suits laterite?
Warm white around 2700–3000 K with good red rendering. Cool white makes laterite look grey and flat.
Is uplighting or downlighting better for facades?
Uplighting is more dramatic but risks glare and sky glow. Downlighting from the parapet looks more natural and keeps light on the building. Tall facades sometimes use both.
Continue the series
- The Night Image
- Uplighting Trees
- Coastal Exterior Lighting: IP, IK and Salt Air
- Light Spill and Dark Skies
- Light the Walls: Vertical Illuminance
About the author
Prem Rout, Founder of JMAP Solutions, set up in 2022 to deliver lighting, automation and building management solutions from Bhubaneswar. Over 15 years of experience in building products, construction and project business development across Mumbai and Odisha, working where design intent meets specification and site delivery. Connect on LinkedIn.
