Task lighting is specified at the surface, not at the fixture. That single distinction explains why a desk lamp with impressive headline output can still leave someone squinting at a keyboard.
Measure where the work happens
Illuminance is measured in lux, or foot-candles in US practice, on the horizontal surface where the task is performed. For reading and paperwork, 300 to 500 lux is comfortable for most adults. Fine work, drafting, or anything involving small parts wants 500 to 750 lux, and casual screen work is comfortable at 150 to 300 lux with good contrast.
| Task | Target illuminance | Notes |
|---|---|---|
| Reading print | 300–500 lx | Higher on the page than the surround |
| Writing and keyboard work | 300–500 lx | Watch for shadow from the writing hand |
| Drafting, model making | 500–750 lx | Directional, from the side opposite the hand |
| Screen work only | 150–300 lx | More light makes screens harder to read |
| Age 60 and over | double the figures | Same task, less light reaching the retina |
Distance is a brutal multiplier
Illuminance falls with the square of distance. Move a lamp head from twelve inches above the desk to twenty-four, and you keep roughly a quarter of the light. This is why head position matters more than output, and why an adjustable arm is usually worth more than extra lumens.
Shadow comes from the wrong side
Place the head on the opposite side to the writing hand, or directly in front and slightly above. A lamp on the same side as the hand throws the shadow of the hand across the page, and no amount of additional brightness fixes that geometry.
Contrast matters more than absolute level
A desk at 600 lux in a room at 40 lux produces eye strain as the pupil adjusts repeatedly. Some ambient light behind the task, even 100 lux from a floor lamp across the room, makes the same desk lamp feel far more comfortable.
What to specify for an office order
Deliverable lumens at the head, colour temperature in the 3000K to 4000K band, a colour rendering index at or above 90 for any environment where documents or colour are judged, and a low-glare diffuser. Add a dimmer, because the correct level for paperwork is the wrong level for a screen.
Sourcing lamps for your business?
We stock the Anrotix range in the United States — complete with LED bulbs and accessories — and supply from 10 units, mixed across SKUs.
Request wholesale pricingRecruiting regional partners worldwide — help@anrotix.cn