Can a physical filter reduce the color temperature? Why?

Physical filters can reduce the color temperature. Color temperature refers to the color characteristics of a light source, usually expressed in Kelvin. A higher color temperature will show blue, while a lower color temperature will show yellow.

Physical filters change the color temperature of light through the transmission or reflection of light, thus reducing or improving the overall color temperature of photos or images. Specifically, when the color temperature decreases, the physical filter will absorb the blue light in the spectrum, so that the proportion of yellow light passing through the filter will increase, thus changing the overall color temperature.

In the field of photography, the widely used physical filters include polarization filter, neutral density filter and gradient filter. They can all change the color temperature by adjusting the propagation mode and transmittance of light.

It should be noted that the effect of physical filter on reducing color temperature is limited, and it is usually used in combination with camera setting and post-adjustment to achieve the ideal effect. In addition, there are digital filters that can simulate the effect of physical filters through software, which is also one of the commonly used means in modern photography.

To sum up, the physical filter can reduce the color temperature by absorbing blue light, thus changing the overall color of a photo or image.