A sequence determination is a type of examination conducted by a forensic document examiner

Questioned document examination

Questioned document examination is the forensic science discipline pertaining to documents that are in dispute in a court of law...

. This type of forensic examination is done in an attempt to determine which of two events occurred first in the preparation of a document. Another term used for this type of examination is "sequence of intersections" since the evaluation requires intersection of physical materials on the document.

Types

• Sequence of Strokes: term for examinations involving two or more writing strokes from one or more writing instruments
• Sequence determinations for writing ink with other types of material:
  • Ballpoint pen
    Ballpoint pen
    A ballpoint pen is a writing instrument with an internal ink reservoir and a sphere for a point. The internal chamber is filled with a viscous ink that is dispensed at its tip during use by the rolling action of a small sphere...
    
     ink/toner
    Toner
    Toner is a powder used in laser printers and photocopiers to form the printed text and images on the paper. In its early form it was simply carbon powder. Then, to improve the quality of the printout, the carbon was melt-mixed with a polymer...
    
     sequence
  • Ballpoint pen
    Ballpoint pen
    A ballpoint pen is a writing instrument with an internal ink reservoir and a sphere for a point. The internal chamber is filled with a viscous ink that is dispensed at its tip during use by the rolling action of a small sphere...
    
     ink/inkjet ink sequence
  • Writing instrument/paper fold sequence
  • Writing instrument/typewriting sequence
• Other sequence determinations:
  • Toner/paper fold sequence

Methods

The primary means of evaluation involves direct visual examination using microscopy and various lighting options. The intersection point may involve subtle deviations from the normal manner of deposition or production that can be observed on microscopic examination (e.g. extraneous ink deposits, skipping, misalignents, embossing, etc.). Lifting/casting technique (see below) have also been tested with some success. Intersections involving indentations may also be assessed using an electrostatic detection device to visualize latent indentations.

• Binocular optical microscopy
• Scanning electron microscopy
• Atomic force microscopy
• Lifting techniques
  • Kromekote paper method
  • Mikrosil casting method
• Electrostatic detection device (EDD) method

Significance

The underlying concept is that each of the sequences will produce a distinctive result that can be visualized or measured.

In some instances, the results will be essentially conclusive with only one reasonable interpretation. In other situations, the results may be less definite in that the observed features may permit more than one interpretation of the original sequence.