Daylight and artificial light differ in their wavelength distribution, which affects their color temperature and overall spectral composition. Here's a breakdown of the differences:
Daylight: Daylight refers to the natural light emitted by the Sun. It is commonly perceived as "white" light, although it actually contains a broad spectrum of colors. Daylight consists of a continuous spectrum of wavelengths, ranging from the shorter violet and blue wavelengths to the longer red and infrared wavelengths.
The color temperature of daylight varies throughout the day. Morning and evening sunlight appears warmer or "soft white," while midday sunlight appears cooler or "bluish white." This variation is due to the angle at which sunlight passes through the Earth's atmosphere, which scatters shorter wavelengths more than longer wavelengths.
Artificial Light: Artificial light refers to any light source created by humans, such as incandescent bulbs, fluorescent tubes, LEDs, etc. Unlike daylight, artificial light often has a more limited spectral composition. The exact wavelength distribution depends on the specific technology used to generate the light.
Different types of artificial lights have different color temperatures, which are measured in Kelvin (K). For instance:
- Incandescent bulbs produce warm white light with a color temperature around 2700K to 3000K.
- Fluorescent lights can range from warm white (around 3000K) to cool white (around 4000K) and daylight white (around 5000K to 6500K).
- LEDs offer a wide range of color temperatures, from warm white to cool white and even daylight white.
Artificial light sources can be designed to mimic the color temperature of daylight. For example, "daylight" bulbs or LEDs are manufactured to emit light in the range of 5000K to 6500K, resembling the color of natural sunlight at midday.
However, even when artificial light matches the color temperature of daylight, the spectral composition may still differ. Daylight usually provides a more balanced and continuous spectrum, whereas artificial light may have specific peaks and gaps in certain wavelengths.
In summary, daylight has a continuous spectrum of wavelengths, while artificial light sources, depending on their technology, often have a more limited spectral composition and can vary in color temperature.