pH Pen -- A Means of Comparing Paper Products

• NCJ Number: 140922
• Journal: Journal of Forensic Sciences Volume: 38 Issue: 1 Dated: (January 1993) Pages: 134-142
• Author(s): R D Blackledge; M N Gernandt
• Date Published: 1993
• Length: 9 pages
• Publication Format: Article
• Publication Type: Report (Technical)
• Language: English
• Country: United States of America
• Note: Paper presented at the Spring Meeting of the Southwestern Association of Forensic Document Examiners, 1991, San Diego, California

Annotation

Printers can use a pH pen to test the alkaline/acid content of paper stock to determine if it will be compatible with a given printing ink, and the pH pen may be useful as an additional discriminator when questioned document examiners attempt to determine if two paper products (known and questioned) could have originated from a common source.

Abstract

In the current study, 68 different white paper products were compared using five different pH pen types. From 2,278 possible pairs, known and questioned, all but six pairs were discriminated by a combination of physical characteristics, fluorescence under ultraviolet light, and the pH pen. The authors point out that, as more mills change to alkaline paper production, the pH pen's ability to discriminate between different paper samples may decrease. 8 references, 5 tables, and 2 figures