Lamps want to be at three heights

There is a measurement that fixes most badly lit rooms, and it is not a lighting-design secret. It is the height of a lampshade relative to the person sitting under it.

Sit in your usual chair. Look straight ahead. The bottom edge of the lampshade on the table beside you should be at roughly that height — the height of your eyes when seated, which is about 100 to 110 cm off the floor for most adults on most sofas.

If the shade is lower, the light comes up at you from below, which is dramatic and terrible for reading. If it is higher, the light comes down onto the top of your head and the book is in shadow. At eye level, the light goes sideways across the room, which is the direction you are looking.

The three heights, with numbers

Low: 40 to 80 cm. A lamp on a low stool, a lamp on the floor, a light under a shelf. Its job is to light the bottom of the room so the furniture does not float in darkness. Without it, everything below knee height disappears after dark and the room reads as cluttered even when it is not.

Middle: 100 to 120 cm. The table lamp. This is the one that lights people. Bottom of the shade at seated eye level, so the bulb is a little above that, around 115 to 125 cm. This is the height at which a room stops feeling like a room and starts feeling like a place where you sit with someone.

High: 150 to 170 cm, or the ceiling. A floor lamp with a wide shade, a pendant, a wall light. Its job is to light the upper wall and stop the room from feeling like it has a lid on it. Above 170 cm you are lighting the ceiling, which is a waste of a bulb.

Three heights, three pools of light that overlap. That is the whole system. It is why hotel rooms and good restaurants feel the way they do, and it is why a room with one bright ceiling light feels like a place where you wait to be seen.

One number worth carrying around: the difference between the tallest and the shortest light in a room wants to be at least a metre. Less than that and the three pools merge into one and you are back to a single flat light with more bulbs in it.

The corner is the worst place for a lamp

A lamp in the corner of a room lights the corner. The light hits two walls at a glancing angle, bounces into the middle of the room as a faint wash, and leaves everything between the lamp and you in shadow. Corners are where lamps go to be decorative and useless.

The better positions are all slightly awkward, which is why people do not use them.

Beside the seat, at the height of the arm. A table lamp on the side table, 15 to 25 cm out from the wall. The wall behind it catches a soft wash, and the light comes across your lap and your book. This is the single best lamp position in a living room.

Behind and to the side of the sofa, not behind your head. A floor lamp at the end of the sofa lights the person at that end and the wall behind them. A floor lamp directly behind the middle of the sofa lights the back of your head and throws your shadow onto the page.

In front of a dark wall. If one wall in the room is dark paint or a dark shelf, put a light near it. Dark surfaces absorb light, so a room with one dark wall reads as dimmer than it is. A lamp in front of that wall gives the room a second source without adding brightness anywhere you do not want it.

Distance from the wall is your dimmer

This is the trick I use most, and it costs nothing.

A shade 15 cm from a wall throws a bright, tight arc up the wall — dramatic, good for a hallway, too much next to a sofa. The same lamp 40 cm out from the wall throws a wide soft gradient and lights the room instead of the wall. At 70 cm it stops being a wall wash and becomes general light.

So before you buy a dimmer, move the lamp. Half the time that is the adjustment you were looking for.

Shades, briefly

A shade is a diffuser. It does three things: it hides the bulb so you are not looking at a point source, it spreads the light over an area, and it decides the colour of what comes out.

Fabric or paper gives a soft, warm edge and lets a little light through the sides, which is why a linen shade makes a room feel calmer than a metal one at the same bulb. Metal, opaque throws light only up and down, which is dramatic and bad for reading. Glass is a compromise and shows every fingerprint.

Width matters more than material. A 20 cm shade makes a spotlight. A 40 cm shade makes a pool. If you are lighting a seat, you want the pool.

One thing worth knowing: a shade that is open at the top throws a bright ring onto the ceiling, and at night that ring is the brightest thing in the room. If you have ever felt a lamp was too harsh despite a warm bulb, look up. A shade with a diffuser on top, or a slightly taller shade, kills the ring.

What I would buy, in order

One table lamp for the seat you use most. Not the prettiest one. The one whose shade lands at eye level when you are sitting down. Measure the table, add the lamp height, check the number. This is the lamp that changes the room, and it is usually the cheapest of the three.

One floor lamp with a wide shade. 155 to 165 cm, shade 35 to 40 cm across, warm bulb. It will do the work of the high light and half the work of the low one, which is why it is worth spending on.

One small low light. A lamp on a stool, a clip light on a shelf, a paper lantern on the floor. This is the one that makes a room feel like it has a base, and it is the one people skip.

And a plug-in dimmer for whichever of the three you use most. Fifteen pounds, and it turns one lamp into three.

The two things this cannot fix

It cannot fix a room with no sockets in the right places. Extension leads are the answer and they are ugly; run them along the skirting behind furniture and stop apologising for them.

It cannot fix a room with no daylight. Lamps make an evening, not a morning. If a room is dark at two in the afternoon, the problem is the window, and no number of lamps will change that.