Government of Ontario

CFS - Technical Information Sheets - Examination for Indentations

Centre of Forensic Sciences

Technical Information Sheets

Documents


Examination for Indentations Information – PDF, 29 kb


Introduction

Indented writing or indentations refers to a latent image that was transferred to a document through pressure exerted on its surface while in contact with an overlying document.

Examination

An item is examined for indented writing using:

  • Oblique lighting together with the unaided eye and/or magnification
  • An Electrostatic Detection Apparatus (ESDA)
Interpretation
Limitations/Factors
  • Fingerprinting using ninhydrin and other solvents inhibits the development of indentations
  • Thickness of paper
  • Storage conditions (i.e. certain acetate coversheets may eliminate indentations)
  • Pressure used to produce the writing on the source item causing the indentations
  • Number/thickness of layers between the questioned and source item
Note
  • Secondary impressions can be transferred from one sheet to another if the two have been in contact for a period of time
  • The absence of decipherable indentations does not necessarily mean the questioned item was never in contact with other items but due to the limitations listed above, the indentations cannot be detected
Significance of findings
  • Can be used to associate two or more documents to each other
  • Can be used as an investigative aid in identifying the possible source of a document
  • Indented writing can be identified as the product of a particular individual

Glossary

ESDA or Electrostatic Detection Apparatus
An electrostatic imaging device used to detect latent impressions on paper products

ESDA Print/Lift
The results of an ESDA examination preserved using clear adhesive film

Oblique Lighting
A light source directed across the document at a low angle