Why can't the camera film see light, but it will be exposed when it sees it? Does exposure mean scrapping?

Exposure, literally, is simply exposing an object to light. The physical meaning of exposure is that light makes the photosensitive layer (coated with photochemical substances) produce a latent image.

For camera film, it is the process that the photosensitive material on the film receives optical images, so the film will be exposed as long as it receives light.

But exposure does not mean scrapping, but if the film is exposed for a long time, the chemicals on the film react completely and fully, and the latent image will become a whiteboard, so it will be scrapped.

The process of pressing the camera shutter button when shooting is the process of film exposure, and the film can be exposed many times. In order to achieve different shooting effects, photographers let the film go back after the first exposure and make a second exposure, which will produce the effect of overlapping two or more photos. Multiple exposures can make photos more fantastic.