When you take a photograph, the light from the scene you're photographing enters the camera and strikes a photosensitive material, typically film or a digital sensor. In traditional photography, the light causes a chemical reaction in the film, creating a latent image. This image is then developed and fixed to create a permanent, light-sensitive record of the scene.

In digital photography, the light striking the sensor creates an electrical charge that is converted into a digital signal. This signal is then processed and stored in a memory card or other digital storage medium. The digital image can then be viewed, edited, and printed as needed.

In both traditional and digital photography, the chemical changes that occur during the process of capturing and recording an image are permanent. This means that the photograph is a permanent record of the scene at the time it was taken, and it cannot be altered or erased without damaging or destroying the photograph itself.