Examination

The examination is the act of making a close and crucial study of any material, and with questioned documents is the process necessary to discover the facts about them. Various types of examination are undertaken including microscopic, visual, photographic, chemical, ultraviolet and infrared document examinations.

Microscopic examination

Any study or examination made with the microscope in order to discover minute physical details.

Oblique light examination

Any examination with the illumination so controlled that it grazes or strikes the surface of the document from one side at a very low angle; also referred to as side light examination.

Transmitted light examination

An examination in which the document is viewed with the source of illumination behind it and the light passing through the paper.

Ultraviolet examination

Ultraviolet radiation is invisible and occurs in the wavelengths just below the visible blue-violet end of the color spectrum. The invisible rays react on some substances so that visible light is emitted, a phenomenon known as ultraviolet fluorescence. Thus, ultraviolet examination may be made visually or photographically, by recording either the reflected ultraviolet or visible radiation.