Replication, in metallography, is the use of thin plastic films to nondestructively duplicate the microstructure of a component. The film is then examined at high magnifications.
Replication is a method of copying the topography of a surface by casting or impressing material onto the surface. It is the commonly-used technique to duplicate surfaces that are inaccessible in metrology to other forms of nondestructive testing.
The replicas may be imaged in the light microscope or coated with heavy metals, the replicating film melted away, and the heavy metal replica imaged in a Transmission Electron Microscope (TEM).
The same materials, cellulose acetate films, are used for creating replicas of biological materials such as bacteria.