What is the principle of comparison?

Contrast refers to the degree of contrast between different things or different aspects of the same thing.

Contrast, also known as density difference, refers to the black-and-white density difference of negative film or photo image and the brightness difference of the subject. A big contrast between light and shade means a big contrast. The contrast is large, indicating that the photo is hard.

Refers to the contrast between light and shade of photosensitive materials. The brightness change of different parts of the scene is the contrast of the scene; The density change of each part in the image is called image contrast, and the relationship between image density and logarithmic change of scene exposure is called the contrast of photosensitive materials.

Black, white and gray reflect different relative brightness. For color photography, it is more complicated, not only the difference in brightness, but also the color? Color and saturation.

Generally speaking, black-and-white films: low-sensitivity films have large contrast and high-sensitivity films have small contrast; Color film: Low-sensitivity film has small contrast and high-sensitivity film has large contrast.