Skip to main content

Forensic Science for Healthcare Professionals

Application of Ultra Violet (UV) Radiations in Questioned Document Examination


Dr. Bhoopesh Kumar Sharma
Forensic Expert & Associate Professor

The questioned documents can consist of identification of fake or genuine cards, contracts, statements, titles and deeds, certificates, stamps, bank checks, handwritten letters, machine-generated documents (such as photocopiers, fax machines and printers), currency and electronic documents.

Out of all light sources, UV and IR are the significant sources of radiation that are widely used in the majority of the Questioned Document examination.

Ultraviolet (UV) is a 10 nm to 400 nm wavelength electromagnetic radiation that is shorter than visible light but longer than X-rays. UV radiation is found in sunlight and contributes about 10% of the Sun's overall electromagnetic radiation production. It is also generated by specialized arcs and lights such as mercury-vapor lamps, tanning lamps, and black lights.

Ultraviolet (UV) illumination techniques are used for multiple purposes in forensic investigations, including authenticating paintings, authenticating signatures, examining the documents in question, ink examination, highlighting latent fingerprints in crime scenes and tracing traces on clothes, detecting ink stains and identifying residual body fluid stains.

In QD examination, there're several types of applications of UV rays. Some are listed below:

1. Paper Examination: UV rays can be used to distinguish between various types of paper and paper textures. When subjected to UV, differently manufactured papers give distinguished fluorescence under UV rays. This is mainly because of the sizing (glazing) of the paper, for example, in some cases, it can appear greenish, and in others, it can be reddish. This is used to differentiate two different types of papers, even having the same experience.

2. Counterfeiting/ Counterfeited Currency or Others: Fake currency notes, security papers, passports, certificates, etc. will give different fluorescent due to the difference in sizing and the fibers present in the documents. Also, specific watermarks (Chemical and Mechanical) can be easily differentiated based on their luminescence under UV rays. Many of these government documents are embedded with multicolor security fibers that glow up in UV rays as red, green, and blue color. However, in fake documents, this will not be the case.

watermarks on bank cheque
A picture showing the presence of water marks on a bank cheque.

Chemical Water-marks as seen under UV light

A picture of a credit card showing fluorescent under UV light.

3. Examination of Alterations in Documents: Usually the spots visible under UV light, may have been treated with any type of ink eradicator. Also, the eruption of the fibers during mechanically erasing of the matter can be evidently visible under UV radiations.

4. Examination of Secret Writings: The secret writing can be made using biological fluids like urine, milk, saliva, semen, vegetable and plant juices, lemon juice, onion juice, quinine hydrochloride, and so on. Since all of these substances produce specific fluorescent under UV light, hence can be deciphered (visualized) and make the matter visible.

Secret Writing

5. Resealed Envelops: An envelop that has been opened and resealed with any type of glue may fluoresce differently under UV light.

6. Paintings Examination: Fraudulently created paintings to showcase them as the genuine work of old times, can be detected by fluorescence test. Usually, varnishes used on an old painting will fluoresce differently from modern varnishes. Other alterations to an original painting can also be detected under UV radiations. 

There can be several other cases of tampered documents, ink analysis, stamp analysis that can be easily performed using UV radiations.

In next section we will discuss the use of Infra-red radiations in the examination of Questioned Documents.


Dr. Bhoopesh Kumar Sharma
Forensic Expert and Associate Professor


  1. Truly one of the best professor I have had!

  2. We read your blog , share most useful information in blog . Buy Genuine Passport Online

  3. This article provided me with a lot of useful information about fake michigan driver's license. The material you presented during this post provided me with some excellent information. Continue to post.

  4. The information which you have shared here . It is a really useful and informative article. I want to encourage you to ultimately continue your great work. Thank you. UV Light Disinfection USA


Post a Comment

Popular posts from this blog

Crime Scene Search Methods

The Crime Scene is search for the physical evidences (visible or invisible). There are various types of search methods employed by the investigating officers and the forensic scientists at the scene of crime. The searching methods mainly depends on: Type of Crime (Rape, murder, burglary, theft, etc.) Nature of Crime (Homicide, suicide, or accident) Size of the crime scene (macroscopic or microscopic) Location of the crime scene (indoor, outdoor, combination of indoor or outdoor, or any remote area like underwater, desert, etc.) Complexity of the crime scene  Before deciding the search method, all the investigators and the forensic experts must follow the general guidelines (check list) to observe the crime scene after due recording: 1. Are the doors and windows locked or unlocked? Open or shut?  2. Are there signs of forced entry, such as tool marks or broken locks? 3. Is the house or the crime scene is in good order? If not, do

Introduction to Forensic Ballistics

By Dr. Bhoopesh Kumar Sharma Forensic Expert & Associate Professor Introduction to Ballistics: The term ballistics refers to the science of study of the action, motion and  behaviour  of a projectile during its flight in any given medium. The flight path of a bullet includes:  • Travel down the barrel  (Internal Ballistics), • Path through the air  (External Ballistics),  and  • Path through a target  (Terminal Ballistics) Forensic Ballistics: Is that branch of forensic science which deals with the examination of the firearm and related evidences encountered at the scene of crime in a shooting incident, and their linkage to the firearm, and Identification of the shooter. A ballistic expert need to answer the following questions: 1. Type of The Firearms used 2. Identification of the Firearm 3. Individual Characteristics of Firearm 4. Range of Firing 5. Direction of Firing 6. Identification of the Shooter 7. Medico legal aspects: - Suic

Blood Spatter Analysis

What is Blood Spatter Analysis? Blood Spatter Analysis or Blood Pattern Analysis (BPA) is the examination of bloodstain shapes, locations, and distribution patterns, to provide an interpretation of the physical events that gave rise to their origin. In forensic investigations, it is ubiquitous to encounter blood on the crime scene. This blood can be in the form of a pool, dried stains, spatter, expirated blood, etc. Hence, the investigators are required to understand these bloodstains to interpret the events that have occurred on the crime scene, to create a possible hypothesis of the modus operandi, to identify the type of weapon, the direction of the blow, severity of the injury, applicable forces, etc. This whole interpretation is known as Blood Pattern Analysis or Blood Spatter Analysis. What are the Types of Blood Patterns? There are many classifications given by blood spatter analyst around the world. I will be using the most common here, to make it understand in