ISSN: 0022-1198
CODEN: JFSCA
Page Count: 9

The pH Pen—A Means of Comparing Paper Products
Gernandt, MN
Senior Chemist and Forensic Document Examiner, Naval Investigative Service Regional Forensic Laboratory, California

Blackledge, RD
Senior Chemist and Forensic Document Examiner, Naval Investigative Service Regional Forensic Laboratory, California

(Received 24 April 1991; accepted 17 June 1992)

Abstract

Printers may use a pH pen to test the alkaline/acid content of paper stock to determine if it will be compatible with a given formulation of printing ink. Questioned-document examiners may find the pH pen useful as an additional discriminator when attempting to determine if two paper products (known and questioned) could have originated from a common source. A total of 68 different fine white paper products were compared. From a total of 2278 possible pairs (questioned and known), all but six pairs were discriminated by a combination of physical characteristics, fluorescence under UV light, and the pH pen.

Keywords:
forensic science, questioned documents, pH pen, paper comparisons, printing, counterfeiting

Paper ID: JFS13385J
DOI: 10.1520/JFS13385J
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