Warm, natural, or cool: which desk lamp setting to use

Color temperature is the difference between a lamp that feels like a bedroom and a lamp that feels like a clinic. If your USB desk lamp has three modes, you do not need to overthink it. Use one rule: match the light to the hour, not to the product page.

Warm (3000K) — evenings and screens-off

Use warm light when you are done with hard focus. Reading, winding down, a nightstand, a shelf behind the monitor. It is softer on the eyes after dark. It is a poor choice if you are color-matching prints or editing photos.

Natural (4500K) — default for work

This is the setting to leave on during the day. It is close to indoor daylight without the blue punch of a garage fluorescent. Good for laptops, writing, and video calls where you do not want a yellow face or a sterile white one.

Cool white (6000K) — short bursts

Cool light makes paper and keycaps look crisp. Use it when you are tired and need the desk to feel awake. Turn it down when you are done. All-night cool light is why people hate desk lamps.

The question-mark USB lamp switches these three modes with one tap. No app, no extra power brick.