Chemical Liquids (867A and 867B) To Reveal Writing Obscured by Printing Ink, Writing Ink and Ballpoint Pen Ink, etc. (From Carnahan Conference on Security Technology, 1989: Crime Countermeasures, P 15-16, 1989, R. William De Vore, ed. -- See NCJ-117867)

• NCJ Number: 117870
• Author(s): S Yan
• Date Published: 1989
• Length: 2 pages
• Corporate Author: People's Republic of China
• Sale Source: University of Kentucky
• Publication Type: Report (Technical)
• Language: English
• Country: United States of America
• Note: Paper presented at Carnahan Conference on Security Technology, Lexington, Ky, May 16-17, 1989.

Annotation

Using the chemical liquids 867A and 867B makes it possible to reveal writing or handwriting that is obscured by printing ink and China ink.

Abstract

These inks contain carbon black, and therefore absorb light with wavelengths in the range of 300 to 1000 nm. When chemical liquid 867A, a milk-white liquid, is applied with a small brush to a document on which the original writing has been covered with a layer of ink, the writing becomes legible in a few moments and is the same color as it was originally. When chemical liquid 867B, a colorless and transparent liquid, is applied to the back side of a document, the original writing is revealed in its true colors. Both chemicals produce readable documents that can be kept for long time periods. These chemicals have been used in both criminal cases and for revealing historical documents. Photographs. (Author abstract modified)