Editing Latent image (section)

==Mechanism of formation==
The action of the light on the [[silver halide]] grains within the emulsion forms sites of metallic silver in the grains. The basic mechanism by which this happens was first proposed by [[Ronald Wilfred Gurney|R.&nbsp;W.&nbsp;Gurney]] and [[Nevill Francis Mott|N.&nbsp;F.&nbsp;Mott]] in 1938. The incoming [[photon]] liberates an [[electron]], called a photoelectron, from a silver halide crystal. Photoelectrons migrate to a shallow electron trap site (a sensitivity site), where the electrons reduce silver ions to form a metallic silver speck. A positive [[Electron hole|hole]] must also be generated, but it is largely ignored. Subsequent work has slightly modified this picture, so that "hole" trapping is also considered (Mitchell, 1957). Since then, understanding of the mechanism of sensitivity and latent image formation has been greatly improved.

A latent image is formed when light changes the charge atoms in the molecule. Taking bromine as a halide for this example, when light hits a silver halide molecule, the halide is changed from a negative charge to a neutral one, releasing an electron that then changes the charge of the silver from a positive one to a neutral one.<ref name="shinsaku">{{cite book |title=Organic Chemistry of Photography |first1=Shinsaku |last1=Fujita |doi=10.1007/978-3-662-09130-2 |publisher=Springer-Verlag |location=Berlin Heidelberg |date=2004 |isbn=978-3-540-20988-1}}</ref>