Knowledge centre
Lighting guides for specifiers and clients
Written by our specification team to answer the questions that actually decide a lighting scheme — optics, colour quality, glare, controls and process. Each guide notes the date it was last reviewed. If a question is not covered, ask us directly.
Process
How to move a project from drawings to a reliable lighting package.
1 guide
Fundamentals
The optical and colour principles behind every good scheme.
3 guides
Fundamentals · 6 min read
Beam Angles Explained: Choosing the Right Optic
Beam angle is the cone of light within which a fitting delivers at least half of its peak intensity, measured in degrees. Narrow optics of roughly 10–20° create focused accents, 24–36° suits general downlighting, and 40–60° or wider gives soft ambient washes. Because beam diameter on a surface is approximately 2 × distance × tan(beam angle ÷ 2), the right optic always depends on mounting height and on what the light is being asked to do.
Read the guideFundamentals · 6 min read
CRI and Colour Rendering: What Ra and R9 Really Tell You
CRI (Ra) scores how faithfully a light source renders eight standard pastel colours against a reference source, on a scale to 100. Because the Ra average excludes saturated red, the supplementary R9 value matters greatly for skin tones, art and food, and a high Ra does not guarantee a good R9. For prime residential and hospitality work, specify CRI 90 or above with R9 of at least 50, and control consistency between fittings with a 3 SDCM colour tolerance.
Read the guideFundamentals · 6 min read
Colour Temperature Guide: From 2200K to 4000K
Colour temperature, stated in kelvin, describes how warm or cool white light appears: 2200K is candle-like, 2700K is the classic warm domestic white, 3000K is slightly crisper, and 4000K reads as cool and functional. Most prime residential interiors are built around 2700K, with 3000K reserved for task-led zones and cooler values kept out of living spaces. The firm rule is consistency — never mix 2700K and 3000K within one sightline.
Read the guideSpecification
Technical depth for specifiers — glare, spacing and controls.
3 guides
Specification · 7 min read
UGR and Glare Control: Specifying for Visual Comfort
The Unified Glare Rating (UGR) scores the likelihood of discomfort glare from an interior lighting installation on a scale where lower is better; common limits are 16, 19, 22 and 25, and EN 12464-1 requires UGR of 19 or below for most office work. UGR is calculated for standardised workplace layouts, so it is not a meaningful metric for homes. Residential glare control instead relies on fitting design — cut-off angles, baffles, deep-recessed sources and honeycomb louvres — and on keeping bright sources away from habitual sightlines.
Read the guideSpecification · 7 min read
Downlight Spacing: Why the Grid Fails and What to Do Instead
Downlights should be positioned for what they light — walls, worktops, art, joinery — not set out on a uniform grid. The old one-per-square-metre habit produces flat, glary ceilings and dark walls; a layered layout with wall-washing at roughly 600–900 mm from the wall for typical 2.4–2.7 m ceilings, plus targeted task and accent positions, uses fewer fittings to better effect. Beam angle and ceiling height, not floor area, determine spacing.
Read the guideSpecification · 8 min read
Dimming Protocols: Phase, 1-10V, DALI and Wireless Compared
Dimming protocols fall into three broad families: mains phase dimming (leading or trailing edge) that chops the supply waveform, analogue 1-10V control, and digital addressable systems led by DALI and DALI-2. Phase dimming needs no control wiring but depends entirely on dimmer-driver compatibility; DALI offers per-fitting addressing, scenes and tunable white via DT8 at the cost of a control bus and commissioning. The protocol, driver and dimmer must be specified together as one decision — mismatches cause flicker, pop-on and dead travel.
Read the guideResidential
Guidance written for prime London homes.
2 guides
Residential · 6 min read
Lighting for Artwork in Prime Homes
Artwork is best lit with adjustable accent fittings aimed at roughly 30 degrees from vertical, using high colour-rendering sources — CRI 90 or above with strong R9 — so pigments read true. The choice between spot, wall wash and framing projector depends on whether you are lighting a fixed work or a changing collection, and gallery practice often limits light-sensitive works on paper to around 50 lux.
Read the guideResidential · 6 min read
Lighting Scenes and Zoning in Prime London Homes
A lighting scene is a stored combination of levels across separately controlled circuits, recalled from a single button — Entertain, Dine, Relax — instead of a wall of individual dimmers. Scenes are only as good as the circuiting and zoning beneath them, which is wiring decided at drawing stage, and they are finished not at handover but at a walk-through commissioning visit once the home is furnished and lived in.
Read the guideCommercial
Sector-specific specification advice for commercial interiors.
2 guides
Commercial · 7 min read
Hotel and Restaurant Lighting: A Specification Guide
Hospitality lighting is specified around atmosphere and faces: warm colour temperatures — often 2200–2700 K in food and beverage areas, 2700–3000 K in guestrooms — tight beams onto restaurant tables with darker surroundings, strict glare control at seated eye level, and dimming that behaves gracefully at low levels. Long-term consistency of lamps and finishes matters as much as the opening-night effect, and emergency lighting compliance remains a separate professional responsibility to coordinate early.
Read the guideCommercial · 6 min read
Office Lighting and Visual Comfort
Standard guidance for office lighting, set out in BS EN 12464-1, calls for around 500 lux maintained on task areas with good uniformity and a Unified Glare Rating of 19 or below for typical screen-based work. Contemporary specification has moved from uniform ceiling grids to task-and-ambient layering, tied to daylight dimming and absence detection — and meeting rooms now need deliberate vertical light on faces for video calls.
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Guides answer the general question; your scheme needs specific answers. Send drawings for a free review, or book a consultation with a London-based specialist.
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