Most people buy a desk lamp the way they buy a lightbulb: by wattage. That is the wrong number. A lamp that is bright but badly placed makes text harder to read, and a lamp that flickers will tire your eyes long before it runs out of output.
This guide covers the four things that decide whether a lamp is comfortable for a full working day, and the features that are mostly decoration.
The difference between task light and room light
A desk lamp is a task light. It exists to light the surface you are reading, not to light the room. That distinction decides almost every other choice.
If the room is already lit reasonably well, a task lamp only has to raise the level on the desk. If the room is dark, one lamp will not fix it, and a single bright source in an otherwise dark room creates the worst reading conditions: a bright pool surrounded by shadow. Your eyes adapt to the brightest thing in view, so the contrast between the lit page and the dark surroundings is what causes strain.
The practical rule: fix the room lighting first, then add a task lamp for the desk surface.
Placement beats brightness
Where the light lands matters more than how much light there is.
A lamp placed in front of you, between your eyes and the screen, puts the bright source directly in your field of view. That is glare, and it makes the screen look dimmer than it is. A lamp placed behind the screen throws light away from you.
The most comfortable arrangement for a desk with a monitor is usually light coming from the side, or from above and slightly behind, so the desk surface is lit while the source stays out of your direct line of sight. If you read from paper as well as a screen, aim the light at the paper, not at your face.
Two details make a large difference:
- A shade you can aim. A fixed head forces you to move the whole lamp.
- A long enough arm. A short arm cannot reach past a keyboard without sitting in front of the screen.
Colour temperature, and why the number matters
Colour temperature describes how warm or cool the light looks, measured in kelvin.
Very warm light, around 2700K, feels like an evening lamp. It is pleasant but tiring for detailed work, because the blue end of the spectrum is reduced and contrast feels softer. Very cool light, above 6000K, looks clinical and can feel harsh late in the day.
A neutral white in the region of 4000K is the practical choice for reading and writing through a working day. If the lamp offers a range, you have the option to warm it in the evening, which is a genuine benefit rather than a gimmick.
Flicker is the specification nobody mentions
Some lamps, particularly cheap LED units and anything with a poor driver, flicker at a frequency you cannot consciously see. The effect is subtle: after an hour of reading, your eyes feel tired in a way that brightness alone does not explain.
You cannot always measure this in a shop. What you can do:
- Prefer lamps that state a flicker-free or low-flicker driver rather than only a brightness figure.
- Test on arrival. Point a phone camera at the lamp on a plain surface. Visible banding across the image suggests the lamp is modulating.
- Avoid the cheapest unbranded units, where the driver is the first thing that gets cut.
The features worth paying for
Adjustable colour temperature is worth having if you work into the evening.
A wide, even spread matters more than a hotspot. A lamp that produces one bright circle on the desk forces you to position everything around it.
A stable base or a clamp. In a small room, a clamp frees desk space and cannot be knocked over. A clamp needs a desk edge thin enough to grip, and it will not work on a glass top.
A USB port in the base is convenient, though it ages badly and can be replaced with a separate charger.
Features that rarely earn their place: touch controls that are hard to find in the dark, apps, and built-in speakers.
A short checklist
- Fix the room lighting before buying a task lamp.
- Choose a lamp with an arm long enough to reach past the keyboard.
- Keep the light source out of your direct line of sight, ideally from the side or above.
- Look for a neutral white around 4000K, or a lamp with a range.
- Prefer a stated low-flicker driver, and test with a phone camera on arrival.
- Prefer a clamp in a small room, and check the desk edge it needs.
- Aim the light at the surface you read, not at your face.
A desk lamp is a small purchase that you use for thousands of hours. Getting the placement and the flicker right matters far more than buying the brightest one on the shelf.
Sources and further reading
- OSHA, Computer Workstations eTool: Workstation Environment. Covers glare and lighting placement, including the point that a bright source in your field of view makes the screen harder to read rather than easier. The placement advice in this article follows that guidance.
- OSHA, Computer Workstations eTool: Monitors, section on viewing time. The eye fatigue guidance there, looking away and blinking at intervals, is worth pairing with better lighting rather than replacing it.
- On flicker: there is no consumer standard that requires a lamp to state its modulation. The phone camera test described above is a practical check, not a measurement, and should be treated as a screening tool rather than proof.