Visualisation of Secret Handwriting by Physical and Chemical Method

Abstract

Secret handwriting is a written note or message that is hidden and written with the help of invisible ink. There is a long history of using invisible ink for secret writing for various purposes. The practise involves writing information using fluids that are hardly visible under normal light. Invisible ink used as writing instruments makes the written message invisible to the reader, thus a visualisation or development technique is required to make the message visible . In this paper we are going to visualise the secret handwriting with both physical and chemical methods that is heat, UV, phenolphthalein and silver nitrate respectively. There’s a lot of physical as well as chemical methods to develop or visualise secret writing, that has been written by using the biological fluids(saliva, milk, tears), chemical fluid(vinegar, saline, baking soda), fruit or vegetables(garlic, ginger, onion, tomatoes, grapes, lemon), secret writing can be developed with the help of UV light, iodine fuming method, candle flame, oven, pH indicators, silver nitrate, phenolphthalein, etc. After the development of handwriting, it’s possible for the Forensic investigator to analyse the writing and identify the person behind it as every individual has individual handwriting characteristics which enables the identification of the suspect. Secret handwriting is most commonly used by the prisoners, criminals, drug dealers, terrorists, international spies, and intelligence departments. Visualisation and development of secret writing is important as it plays significant role in identifying the suspect, and it helps to solve the crime through the analysis of the handwriting, verification of documents, historical document analysis.