Both monochrome and color cameras share the same fundamental imaging principle: an image sensor (such as CMOS) converts light signals entering through the lens into electrical signals, which are eventually processed into digital images.

The working principle of a monochrome camera is relatively straightforward. Each pixel on its image sensor only detects the intensity, or grayscale value, of incoming light, recording tonal gradations ranging from pure black to pure white to form a grayscale image rich in fine details and layering.

Imaging with a color camera is more sophisticated. A color filter array known as the Bayer filter is placed in front of its image sensor. This array consists of red, green and blue primary color filters, with each pixel only capturing luminance data for one single color. The camera then applies complex interpolation algorithms to extrapolate the missing two color channels for every pixel based on color information from adjacent pixels, ultimately synthesizing a full-color image.

In short, monochrome cameras record only light intensity, while color cameras capture chromatic information of light via spectral decomposition and reconstruction.