Authentication by the study of the structure of the materials present in the object

Techniques allowing a vision of inaccessible zones of the object

Endoscopy

a. Principle :

consists in enlighting and possibly magnifying the surface of an object's area which is usually inaccessible

b. Applications :

endoscopy allows to examine the inner surface of vessels fitted with narrow necks

c. Advantage :

to be able to examine areas which are very difficult to reach by forgers

Other techniques of "in depth" vision : reflectography - radiography - gammagraphy
Other techniques of magnification : stereoscopy - electron microscopy - metallography