The colour temperature of the light emitted by the lamp. The overall colour of the glow depends on this indicator; and note that the higher the colour temperature, the more “cold” the light looks, the closer it is to blue and blue. Traditional incandescent bulbs produce warm light at 2500-3000K, 3000-3500K can be described as "slightly warmer than neutral", neutral white corresponds to temperatures of
3700-4500K, higher values correspond to cooler shades, and temperatures
over 5000K characteristic of lamps with a blue (blue) colour of the glow.
Note that in this case the colour temperature of the lamp itself (more precisely, its filament or LED element) is indicated, and not the actual shade of the glow that it will give out; for the difference between these indicators, see "Glow colour". Also note here that it is possible to evaluate the shade of light by colour temperature in headlight lamps (see "Intended use"), for which the white colour of the glow is claimed. At the same time, this indicator has a very practical meaning: the warm colour of the light is considered optimal in wet weather, the neutral one gives the highest visible brightness, all other things being equal, and the cold “long-range” one can be subjectively pleasant for some drivers, and can also be used as an element of external tuning.
The level of increased brightness provided by the lamp. This indicator is used by some manufacturers for marketing purposes: it describes how brighter a given model is than some "standard lamps". At the same time, the standards for comparison may be different, and impressive figures (in some models reaching 140%, that is, almost 2.5 times) are not always reliable — that is, a high-brightness lamp will not necessarily be just that much brighter than the “normal” model of the same type and power.
