The first Nimbus prototype was too heavy. It stood on the bench like a paperweight, and the moment one of us lifted it we understood what we had really been drawing. A lamp belongs to a table. This one was meant for a hand. Everything that followed was subtraction.

Turning the body

The body is turned from a solid billet of aluminium on a lathe older than most of the people who run it. The cutter takes the metal down in passes no thicker than a fingernail, and between passes the piece is measured twice: once with a caliper, once with a thumb. The wall ends at two and a half millimetres. Any thinner and the shade rings when you set it down. Any thicker and the lamp stops being something you carry and becomes something you move.

Then the surface. Each body is brushed by hand in one direction only, so the grain runs the length of the cylinder and the light that touches it travels instead of scattering. The finish goes on in three thin coats, cured between each, and the last is sanded back with a grade so fine there is nothing left to see. Colour on a portable lamp is a hard problem, because it will be handled, knocked, set down on stone and on wood. We chose a pigment that marks, and then agreed that marking was the point.

A shade thinned until light could pass

The shade gave us the most trouble. It is a resin we mix in small batches, poured into a mould, then pared back on the wheel until it turns translucent at the crown and stays almost opaque at the rim. That gradient is what makes the Nimbus behave: bright enough to read by underneath, quiet enough to sit beside a face across a table. No two shades leave the bench with the same density. We spent a season trying to correct it. Now we sign the inside and let it be. Four pairs of hands touch every Nimbus before it leaves us:

• Turning — the body cut from billet, bored, threaded at the base.
• Brushing — one direction, by hand, until the grain reads as a single line.
• Pouring — the shade cast in small batches, cured a week before it is pared.
• Assembling — cell, driver and dimmer seated, the joint closed, the weight checked against a reference piece.

Portable is a promise about weight, and weight is a promise about trust. We spent a year taking things away from this lamp, and what remains is what a hand can hold and a room can use. Light, carried.