Visible image of latent image formation during plate making

To change the latent image into a visible image, the silver atoms at the development center must continue to increase until the human eye can clearly observe it. This is accomplished through the action of development.
The purpose of the development is to reduce the silver ions of the silver salt molecules in the photosensitive layer emulsion layer to the silver atoms, which is the same as the exposure, but it is done by drugs. Therefore, the development can be regarded as the continuation of the exposure.
There are many drugs that can reduce halogen silver in development, and they are all easily oxidizable chemicals. The principle of development is described with respect to hydroquinone as an example. The hydroquinone is ionized in the developer as follows:
The anion is the imaging ion, which is easily oxidized to acid and emits two electrons.
Halide silver gets electrons reduced to silver.
The combined reaction of halogen ions and red ions to generate halothane is as follows:
Exposure has a light receiving portion and an unlighted portion, and the developer acts on the entire surface of the photosensitive layer, but why is only the halogen silver at the developing center reduced to silver? This is because potassium bromide is added to the developer and it ionizes Br in the solution.
The development center is a silver atom, it is impossible to adsorb Br, only Ag+ will adsorb it. Therefore, in addition to the development center, they are all surrounded by Br, forming a negative barrier. In this way, the developing ions enter the crystal from the gap in the developing center, so that the silver halide is reduced to silver.