SF 27 and SF 28: TECNOLUMEN's Adjustable Bauhaus Desk Lamps

A desk lamp earns its place by putting light exactly where the work is and nowhere else. The SF 27 and SF 28, two Swedish functionalist lamps of the late 1920s now made again by TECNOLUMEN in Bremen, reach that goal by opposite routes: one with a swinging, jointed arm, the other with a glass sphere and a loose metal cap. This piece explains how each one adjusts, what that means at a real desk, and where the later LUM 50 fits in.

Light as an instrument: the late 1920s

In the late 1920s a wave of functionalist lighting swept Europe, and the Bauhaus workshops in Dessau were redefining what a lamp should be: not an ornament, but an adjustable instrument for working light. Movable joints and rotating reflectors, the function points popularised by designers such as Christian Dell and Marianne Brandt, were the great innovation of the period. They let the user direct light precisely where it was needed, onto a sheet of paper or a writing table, at a time when bare electric light was still harsh and new.

The same thinking was not confined to Germany. In the Netherlands, Willem Gispen made opal glass a functionalist signature with his Giso lamps, and Swedish designers worked in a movement that ran parallel to the Bauhaus workshops. The SF 27 and SF 28 belong to that international moment rather than to one school. That is why TECNOLUMEN, a company founded in Bremen in 1980 by Walter Schnepel and known first for its re-edition of Wilhelm Wagenfeld's WG 24, has made it its mission to keep this chapter of design history in production.

SF 27: the swinging arm

The SF 27 Bauhaus Table Lamp dates from 1927 and was rediscovered in Sweden. Its whole character comes from what its makers call function points: rotating, movable joints that link straight chrome-plated rods to a round baseplate and to the reflector. Each joint turns independently, so the lamp can be folded upright and compact, or opened into a long diagonal that leans out over the desk.

The numbers explain why that matters. The SF 27 reaches a height of up to 680 mm and a reach of up to 570 mm from a base of Ø210 mm. In practice, the base can sit at the back corner of a desk while the reflector hangs over the centre of the work area, leaving the surface in front of you clear. Lower the arm and the light becomes a tight, bright pool on a notebook; raise it and the pool widens to cover a laptop and papers side by side.

The materials are chromed and nickel-plated metal. The function points come in brass or chrome, and that choice changes the mood considerably: brass joints read as warm accents against the chrome rods, while an all-chrome lamp looks more like a piece of laboratory equipment. Every SF 27 is consecutively numbered and carries the TECNOLUMEN logo, and it is made in Germany.

Living with it, the SF 27 rewards a moment of setting up. Because the joints hold their position, you adjust it once for a task and it stays there until the task changes. It is the better lamp for anyone who writes by hand, sketches, or moves between screen and paper through the day.

SF 28: the fixed stand and the tilting cap

The SF 28 Bauhaus Table Lamp was developed in 1928 by a Swedish functionalist group, and it is close in spirit to Gispen's Dutch designs. Where the SF 27 adds joints, the SF 28 removes almost everything. A polished-aluminium cap rests loosely on an opal-glass hemisphere and is held only by friction. There is no arm to swing and no hinge to tighten. To redirect the light, you tilt the cap by hand, and it stays where you leave it.

The dimensions are modest: 165 x 390 x 165 mm overall, with a shade of Ø160 mm and a base of Ø165 mm. The frame is chromed and black-lacquered metal. Like its sibling, each SF 28 is made in Germany and consecutively numbered with the TECNOLUMEN logo.

This is the real difference between the two lamps. The SF 27 moves the light source itself, closer or further, higher or lower. The SF 28 keeps the light source in one fixed position and changes only where the cap sends the glow. The opal glass diffuses the bulb in every direction, and the cap shields the eye and pushes more light to one side. The result is soft, glare-free light rather than a sharp task beam.

On a desk, that makes the SF 28 a companion light: good for reading, for a video call where you want your face evenly lit, or for a corner of a large desk that needs a calm glow. It also moves easily to a bedside table or a hallway console, where the SF 27's long reach would be wasted.

Side by side at the desk

A simple rule works for most people. If the lamp's main job is to light a specific spot, choose the swinging arm. If its main job is to make a desk or a corner feel comfortable to sit at, choose the fixed sphere. Many studies benefit from both: the SF 27 over the work, the SF 28 at the edge of the desk or on a shelf behind it.

LUM 50: the same idea in tubular steel

For a contemporary take on adjustable Bauhaus light, the LUM 50 Table Lamp by Ulf Möller, introduced in 2010, is worth considering alongside the two historical designs. It is built from a continuous 20 mm tubular-steel frame, the material language Thonet made famous with cantilever chairs, and each piece is stamped "THONET by TECNOLUMEN". It stands 500 mm high, and its horizontal arm rotates through 360 degrees.

Its adjustment sits between the other two. Like the SF 27, it moves the light across the desk; like the SF 28, it does so without joints to set or tighten. An integrated energy-efficient LED gives bright yet glare-free light, and the slim frame keeps sightlines open on a narrow desk. It comes chromed or lacquered in black or white.

Placing an adjustable lamp well

• Put the base on the side opposite your writing hand, so the arm or light does not cast the shadow of your hand across the page.
• With the SF 27, keep the reflector a little above eye level when seated and angle it down, so you see the lit surface rather than the light source.
• With the SF 28, turn the cap towards the wall or the screen to reduce reflections, and let the opal glass do the rest.
• On a shallow desk, the LUM 50's rotating arm or the SF 28's compact footprint will usually fit better than the SF 27's full reach.

Both Swedish lamps sit comfortably next to Wagenfeld's glass-and-metal design; our piece on the WG 24 and the Bauhaus metal workshop covers that story in detail. To compare these designs with other desk and bedside options, see the full Table Lamps collection.