Colour temperature describes the apparent warmth or coolness of a light source, measured in kelvin (K). Lower numbers look warmer; higher numbers look cooler. It is a planning language, not a rule that every photograph must be neutral.
| Temperature | Common look | Useful for |
|---|---|---|
| 2700K–3200K | Warm, amber | Evening interiors, food, a deliberately cosy scene |
| 4000K–4500K | Neutral-warm | Mixed indoor light, skin and tabletop work |
| 5000K–5600K | Daylight-neutral | Product photography, window-light matching |
| 6500K+ | Cool, blue | Overcast scenes, a crisp editorial or technical mood |
Match first, stylize second
When there is more than one source, start by matching your added light to the dominant light in the frame. A warm lamp and a daylight window can make skin look split in two. If you want that contrast, make it clear and repeatable; if you do not, turn one source off or bring them closer together.
For a product shot by a window, begin around 5000K–5600K. For a late-night scene lit mostly by lamps, begin closer to 3000K. Then look at white objects in the frame. If white paper looks unexpectedly blue or orange, you have a useful diagnostic.
Do not confuse brightness with temperature
A brighter light is not automatically cooler, and a dimmer light is not automatically warmer. Brightness controls exposure; colour temperature controls the tint of the source. Adjust them separately. That one habit makes small lighting setups easier to repeat.
With Lumet, save the settings that worked for a setup: the screen position, brightness, temperature and distance from the subject. The point is not to memorize kelvin values. It is to recreate a result you liked without beginning a fresh argument with your desk lamp.