A growing, plain-English dictionary of the lighting words we use across the JagMag Lights blog. No jargon, no fluff — just what each term actually means and why it matters when you’re choosing a light. Jump to the term you need.
Colour temperature (Kelvin, K)
Colour temperature describes whether a light looks warm and orange or cool and blue. It’s measured in Kelvin (K) — think of it as a dial: low numbers (2200–2700K) glow candle-warm, the middle (3000–3500K) is a soft neutral white, and high numbers (4000K+) feel like crisp daylight. Warm light feels relaxing and flattering, which is why hotels, restaurants and homes usually pick 2700K–3000K for the spaces where people gather. Cooler light reads as clinical or “awake,” so it suits offices and task areas more than a lobby or dining room. The simplest rule: the more you want a room to feel calm and welcoming, the lower the Kelvin number you choose.
CRI (Colour Rendering Index)
CRI is a 0–100 score for how truthfully a light shows colours, compared with natural daylight. A bulb with a high CRI makes skin, food, fabric and wood look the way they really are; a low-CRI bulb can leave faces looking grey and food looking off. For anywhere people are photographed or served food — weddings, lobbies, banquet halls, restaurants — aim for CRI 90 or above (95+ for food). It’s one of the most overlooked numbers in lighting, yet it’s the difference between a space that photographs beautifully and one that looks flat.
Lumens and lux (how bright it really is)
These two get muddled constantly. Lumens measure the total light a bulb or fixture pumps out — it’s a property of the lamp. Lux measures how much of that light actually lands on a surface, like a tabletop or floor — it depends on the room, the height and how many fixtures you have. So a single bright chandelier (lots of lumens) can still leave a big hall dim (low lux) if it’s the only source. That’s why designers plan light levels in lux across the whole space, not by buying one powerful fixture. As a rough guide, hotel lobbies and circulation areas are typically lit to around 150–300 lux, with task spots brighter.
LED
An LED (light-emitting diode) makes light from tiny electronic chips instead of a hot wire or gas — the same family of tech as your phone’s torch. Compared with old halogen or incandescent bulbs, LEDs use a fraction of the electricity, last many times longer (often 15,000–50,000 hours), and stay cool to the touch instead of running scorching hot. For a big fixture with dozens of lamps high above a crowd, that means far lower running costs and far fewer trips up a ladder to change bulbs. Modern LEDs come in every colour temperature and can be fully dimmable, so you no longer trade efficiency for a warm, flattering glow.
Dimmer
A dimmer is a control that lowers a light’s brightness instead of just switching it on or off. It’s the single most useful upgrade for any decorative fixture, because one chandelier can then do two jobs: bright and lively for arrivals or dancing, soft and intimate for dining or speeches. One catch worth knowing — LEDs need a dimmer that’s specifically LED-compatible, or you can get flicker or buzz. Some premium fixtures also offer “warm dimming,” where the light not only gets dimmer but also warmer (3000K → 2200K) as you turn it down, mimicking the cosy glow of old bulbs.
Flush vs semi-flush mount
A flush mount is a fixture that sits flat against the ceiling with no drop; a semi-flush hangs down just a few inches. Both are the go-to choice when a ceiling is too low for a hanging chandelier to clear people’s heads safely. As a rule of thumb, the lowest point of any hanging fixture should stay at least about 7–7.5 feet (≈2.1–2.3 m) above the floor, so in a standard-height room a flush or semi-flush keeps the look without the head-bump risk.
Chandelier lift (motorised hoist / winch)
A chandelier lift is a motorised winch mounted in the ceiling that lowers a heavy fixture down to a safe working height for cleaning or bulb changes, then raises it back. In tall lobbies and banquet halls — where a chandelier might hang 6–10 metres up — a lift turns a scaffold-and-shutdown job into a routine task, and removes the risk of working at height. Commercial systems carry loads from around 100 kg up to 450 kg or more, and many lock onto rigid ceiling supports (rather than dangling from the cable) once raised. If you’re specifying a large fixture for a high ceiling, planning the lift in from the start is far cheaper than retrofitting one later.
More terms are added as new guides reference them. Spotted one we should explain? It probably means we owe you a clearer article.