A color temperature meter is primarily used to measure the color temperature of a light source, which is expressed in Kelvin (K).

Color temperature is the perceived warmth or coolness of a light source, and it affects the overall color cast of a photograph. A higher color temperature (e.g., above 5000K) produces a cooler, bluish cast, while a lower color temperature (e.g., below 3200K) produces a warmer, reddish cast.

A color temperature meter works by measuring the color temperature of a light source by comparing it to a known reference. It typically uses a sensor that is sensitive to different wavelengths of light, and it calculates the color temperature based on the relative intensities of these wavelengths.

There are several types of color temperature meters available, including contact color temperature meters, non-contact color temperature meters, and spot color temperature meters. Contact color temperature meters are placed directly on the light source, while non-contact color temperature meters measure the color temperature from a distance. Spot color temperature meters measure the color temperature of a specific area within a scene.

To adjust the white balance of a camera using a color temperature meter, you can either set the camera's white balance to the color temperature reading, use the color temperature reading to manually adjust the camera's white balance settings, or use the color temperature reading to create a custom white balance preset.

The accuracy of a color temperature meter can be affected by several factors, including the type of light source being measured, the distance between the meter and the light source, and the angle at which the meter is pointed at the light source.

Using a color temperature meter when shooting in different lighting conditions is important to ensure accurate color reproduction in photographs, prevent color casts, and achieve a consistent look and feel across a series of photographs.

Color temperature meters have applications beyond photography, including lighting design, filmmaking, and video production.

To maintain the accuracy of a color temperature meter, it is important to calibrate the meter regularly, store the meter in a cool, dry place, and avoid exposing the meter to extreme temperatures.

Color temperature meters have some limitations, including the fact that they can only measure the color temperature of a single light source, they cannot measure the color temperature of mixed light sources, and they are not always accurate in low-light conditions.