What's the difference between a negative and a photograph?

Photographic film is also photographic film. Film is silver salt sensitive film, also called film. Made of PC/PP/PET/PVC. Photographic film is made by coating silver halide on acetic acid film base. When light shines on silver halide, silver halide becomes black silver, which is fixed on the film base after development and becomes a common black-and-white negative. Color negative is coated with three layers of silver halide to show three primary colors. In addition to negative films, there are positive films, one-time imaging films and so on.

Photographic negatives are often called inverted black and white, because the camera itself uses twice as many objects as those placed out of the focal length of the convex lens. So the people and images in the photographic film are actually upside down. The negative film is coated with sensitizer. When people take pictures, because the light-colored part has strong light-reflecting ability, the reflected light enters the camera's black box and the sensitizer in the negative film produces photochemical effect. The dark part has high light-absorbing ability, and only a small amount of reflected light enters the negative film, so the light-colored part is very sensitive in the negative film, while the light-colored part is just the opposite and weak. In the process of developing film, the photosensitive agent in the weak photosensitive part is easily washed away, so it is basically light color. The part with strong light sensitivity has photochemical reaction and can't be cleaned, so the color is dark.