A desk lamp must enable precise work without straining the eyes. Many users complain about headaches or quick fatigue because the lamp glares, provides too little light, or does not properly illuminate the work area. The choice of the right lamp depends on measurable quantities: luminous flux in lumens, arm length in centimeters, and the position of the light source relative to the work surface. Knowing these parameters allows you to specifically select a lamp that supports concentrated work for several hours.
Glare-free thanks to shielding and bulb position
Glare occurs when the eye looks directly into the light source or when light is reflected from shiny surfaces. A glare-free desk lamp hides the bulb behind a shade or baffle so that only directed light hits the work surface. The tilt angle of the shade should be adjustable so that you can adapt the light direction to the position of your eyes. Make sure that the shade is made of matte material or is coated white on the inside to minimize scattered light.
For lamps with visible bulbs, such as filament LEDs, the light source should be at least 40 centimeters from the edge of the table and not positioned higher than eye level when seated. Check if the lamp has a dimmer: this allows you to adjust the brightness to the time of day and ambient light, further reducing glare.
Luminous flux in lumens for various activities
The luminous flux, measured in lumens, indicates how much light a lamp emits in total. For desk work, DIN EN 12464-1 recommends an illuminance of 500 lux on the work surface. To achieve this value, you need about 400 to 600 lumens for a lamp with a focused beam of light if the distance between the bulb and the table surface is 40 to 50 centimeters. For technical drawing or detailed work, it should be 600 to 800 lumens.
Note that the specified lumen value refers to the total luminous flux. For lamps with a shade or reflector, only a part of it reaches the work surface. A lamp with 500 lumens and a narrow beam angle of 30 degrees provides more usable light on the desk than one with 700 lumens and a diffuse all-round beam.
Arm length and reach over the work surface
The arm length determines how far the light source extends over the table surface and which areas can be illuminated. A single arm of 35 to 45 centimeters in length covers a work surface of about 60 by 80 centimeters if the lamp is placed at the edge of the table. For larger desks from 140 centimeters wide, you either need a lamp with two articulated arms that together offer 60 to 80 centimeters of reach, or you position the lamp centrally on the table.
Articulated lamps with multiple arm segments allow for precise adjustment. Before purchasing, measure the distance between your usual seating position and where the lamp will be placed. Add 15 centimeters of reserve so that you can also move the light source sideways without having to move the base.
Color temperature and color rendering
The color temperature, specified in Kelvin, influences concentration. For office work, values between 3500 and 4500 Kelvin are suitable, a neutral white light that appears neither too warm nor too cool. Values above 5000 Kelvin produce a daylight-like, bluish light that has an activating effect but can be perceived as unpleasant with prolonged exposure.
The color rendering index CRI should be at least 80, preferably 90 or higher. A high CRI ensures that colors on paper or screen appear true to life, which is important for graphic work or when reading colored documents. This information can be found in the bulb's data sheet.
Mounting and stability
Desk lamps are either placed on the table or attached with a clamp. Floor lamps require a heavy base, at least 1.5 kilograms for arm lengths up to 40 centimeters, so that the lamp does not tip over when adjusted. Check whether the base has a non-slip coating or if rubber pads are present.
Clamp lamps save space on the work surface and can be attached to tabletops up to about 5 centimeters thick. The clamp should be equipped with a protective mat to prevent pressure marks on the tabletop. Measure the thickness of your tabletop before ordering a clamp lamp.
Guidelines for desk lamps
| Parameter | Recommended Value |
|---|---|
| Luminous flux for reading and writing | 400 to 600 lumens |
| Luminous flux for detailed work | 600 to 800 lumens |
| Arm length for tables up to 120 cm wide | 35 to 45 cm |
| Arm length for tables from 140 cm wide | 60 to 80 cm (two arms) |
| Color temperature | 3500 to 4500 Kelvin |
| Color rendering index CRI | at least 80, preferably 90+ |
| Distance from bulb to table surface | 40 to 50 cm |
| Weight of base (for 40 cm arm) | at least 1.5 kg |
Selection criteria summarized
- Measure the width and depth of your work surface to determine the necessary arm length.
- Choose a lamp with a dimmer to adjust the brightness to changing light conditions.
- Ensure a fully shielded shade or a bulb position outside the direct line of sight.
- Check if the lamp has multiple joints so you can precisely adjust height and angle.
- Check the lumen and color temperature specifications in the data sheet, not just the wattage.
- For clamp lamps: Measure the thickness of the tabletop and check if a protective mat is included.
You can find suitable pieces under Desks and Table Lamps. Details on how the pieces are constructed, available dimensions, and delivery times can be found on Eichholtz Desks and Eichholtz Table Lamps.
Frequently Asked Questions
How many lumens does a desk lamp need for computer work?
For screen work, 400 to 500 lumens are sufficient, as the monitor itself emits light. More important is that the lamp does not reflect on the screen. Position the light source to the side, about 30 degrees offset from your line of sight, and dim the light so that no reflections appear on the display. With matte screens, you can also work with 600 lumens if you frequently switch between paper and screen.
What arm length is suitable for a desk 160 centimeters wide?
For this width, the lamp should either have two arm segments with a total reach of 70 to 80 centimeters, or you should place two separate lamps at both ends of the table. A single lamp with a 40-centimeter arm will only cover about half the area. Alternatively, you can position a lamp with a long arm centrally on the table, but this takes up space on the work surface.
Is a higher color temperature better for concentration?
Light above 5000 Kelvin has an activating effect but can be perceived as too cool and strenuous during several hours of work. Neutral white light between 3500 and 4500 Kelvin offers a good compromise: it promotes alertness without over-straining the eyes. For evening hours, you can dim to 3000 Kelvin if your lamp has a color temperature control, to prepare the body for rest.
How do I prevent reflections on glossy table surfaces?
Direct the lamp so that the light beam hits the work surface at an angle, not perpendicularly. An angle of about 45 degrees to the tabletop minimizes reflections. Choose a lamp with an asymmetrical reflector that directs the light specifically downwards instead of scattering it diffusely. For highly glossy surfaces, a desk pad made of matte material that covers the area directly under the lamp helps.