Forensic document examination is the scientific examination of documents to establish whether they are genuine, whether they have been altered, how they were produced and, in handwriting cases, who wrote them. It relies on non-destructive optical methods first: magnification, light from different angles, ultraviolet and infrared light, and comparison against known reference material.
This page sets out what the discipline covers, the sequence in which an examination is carried out, the equipment used at each stage and the standards that shape the work. It is written for examiners, laboratory managers and the organisations that equip them: police, border and immigration services, banks and independent laboratories.
What forensic document examination covers
The work is defined by the questions it answers. Those questions fall into a small number of groups.
Authenticity of security documents. Passports, identity cards, residence permits, visas, driving licences and banknotes carry deliberate security features. The examiner checks substrate, print processes, personalisation and security features against a reference for that document type and issue.
Alterations. Additions, erasures, overwriting, chemical removal of ink, substituted photographs and replaced pages. Alterations leave physical traces in paper, ink and laminate that optical methods can reveal. See detection of chemical alterations in documents.
Production and origin. Which printing or personalisation process made the document, whether two documents came from the same source, and whether a counterfeit links to others.
Writing. Whether entries were made with the same ink, in what sequence, and whether impressions of writing from another sheet are present on the page.
Handwriting and signatures. Comparison of a questioned signature or handwriting with known samples. This is a specialist field within the discipline with its own training and methods.
Any document whose authenticity, origin or content is in doubt can become the subject of an examination. In the field, such a document is called a questioned document, which is why the discipline is also known as questioned document examination.
The examination sequence
A forensic document examination follows a fixed sequence, from methods that leave the document untouched to those that may affect it. The order protects the evidence and ensures that nothing is missed.
1. Visual examination
The document is examined in good white light without magnification. Layout, print quality, alignment, colours, wear and damage are noted. This stage forms the first hypotheses and decides where to look in detail.
2. Magnification
A loupe at 10x to 15x resolves microprint, the dot or line structure of printing processes, laser engraving and the condition of paper fibres. A microscope at higher magnification then gives detail on line crossings, pen strokes, erasure damage and print defects. Our comparison of manual magnifiers and digital microscopes sets out what each contributes.
3. Oblique light
White light at a low angle across the surface shows relief: intaglio print, embossing, raised laser engraving, paper disturbed by erasure and indented writing. It is one of the simplest methods and often one of the most informative.
4. Transmitted light
Light from behind the document shows watermarks, security threads, laser perforations, and paper that has been thinned by scraping. On booklets it also shows whether perforations line up through the pages.
5. Ultraviolet light
At 365nm, UV light excites fluorescent security features, fibres and planchettes, and reveals optical brighteners in paper that should be UV dull. Shorter wavelengths such as 254nm show features designed for short-wave UV. Chemical treatment of paper often changes its UV response. The principle is explained in how UV light reveals document forgeries.
6. Infrared light
Inks that look identical in visible light often behave differently in the infrared. Under IR, an added digit or a changed entry can appear lighter, darker or disappear while the original remains. IR luminescence, where an ink excited by visible light emits in the infrared, adds a further way to separate inks. See infrared examination and what infrared reveals that UV cannot.
7. Comparison
The findings are compared against reference material: genuine documents of the same type and issue, known writing samples, or other questioned documents in the same case. For identity and travel documents, PRADO, the public register maintained by the Council of the European Union, describes genuine documents and their features.
8. Further methods
Only after the optical examination is complete and recorded does an examiner consider methods such as electrostatic detection of indented writing or chemical analysis of ink. These are laboratory methods and some affect the document.
Combining stages 2, 5 and 6 into one efficient routine is covered in combining IR, UV and magnification in one examination.
Equipment per stage
The equipment follows the sequence. The table shows which instrument type serves each stage, with the relevant product category in our range.
| Stage | Instrument type | Dexeq category |
|---|---|---|
| Magnification, first look | Handheld loupe at 10x to 15x, ideally with built-in light | Manual inspection magnifiers |
| Magnification, detail and capture | Digital or USB microscope | Microscopes |
| Oblique and transmitted light | White light at low angle and from behind, often integrated in magnifiers | Manual inspection magnifiers |
| Ultraviolet | UV flashlight at 365nm, plus 254nm or 313nm where needed | UV flashlights |
| Infrared | Portable IR camera at 850nm | IR cameras |
| Combined examination | Desktop system with white, UV and IR light, magnification and display | Forensic examination systems |
A few notes on choosing within each stage:
- Magnifiers with integrated light save time. A handheld unit that combines magnification with white, oblique and UV light allows the first four stages without changing tools. The 15x Magnifier DXQ is an example, with oblique white light and UV in one housing.
- Image capture matters as soon as findings are reported. A microscope or camera with a scale in the image turns an observation into a record. See recording a finding.
- IR wavelength choice matters. Different inks separate at different wavelengths. Our guide on choosing the right IR wavelength explains the trade-offs.
- Desktop systems bring repeatability. The Forensic Examinator combines top, oblique, side and transmitted white light, UV at 365nm and 254nm, IR at 850nm and 940nm and 980nm anti-Stokes light with 3x and 5x optical and 8x to 100x digital magnification on a 7 inch display.
For an overview of all equipment categories, from handheld tools to examination systems, see our guide to document authentication equipment.
Standards that shape the work
Forensic document examination is a discipline with published standards and best practice guidance. They do not prescribe equipment brands, but they do shape how examinations are carried out, recorded and reported.
Scope of work and examination procedures. In the United States, consensus standards describing the scope of work of forensic document examiners and procedures for specific examinations were developed under ASTM International and are now developed through the forensic science standards bodies, with approved standards listed on the OSAC Registry (OSAC is administered by NIST). They cover topics such as the examination of handwriting, indentations, alterations and printing processes.
European best practice. The European Network of Forensic Science Institutes (ENFSI) has expert working groups for documents and for handwriting that publish best practice manuals and organise collaborative exercises among member laboratories.
Laboratory accreditation. Forensic laboratories commonly work under a quality management system and accreditation for testing laboratories, which requires validated methods, documented procedures, calibrated equipment and competence testing of staff.
Travel document specifications. ICAO Doc 9303 is not a forensic standard, but it defines the layout and machine readable elements of passports and other travel documents. That makes it the baseline against which travel documents are examined. See ICAO 9303 explained.
In practice, the standards translate into habits: a fixed sequence, non-destructive methods first, every step recorded, conclusions expressed on a defined scale, and equipment that is maintained and checked.
Setting up a workstation versus a full laboratory
Not every organisation that examines documents needs a laboratory. The right setup depends on the questions asked and on whether results must stand up in court.
An examination workstation suits banks, notaries, border posts and police units that check documents and refer the difficult cases. It typically includes:
- a handheld magnifier at 10x to 15x with white, oblique and UV light;
- a UV flashlight at 365nm and, where documents require it, at 254nm or 313nm;
- a portable IR camera;
- a digital microscope for image capture;
- a transmitted light source and a workspace where ambient light can be reduced;
- access to reference material for the documents seen most often.
Lighting in the room has a direct effect on UV and IR work, as described in workstation lighting.
A forensic laboratory adds the capabilities needed for formal expert reports: spectral comparison instruments, electrostatic detection of indentations, handwriting comparison, ink analysis, validated procedures, proficiency testing and accreditation. Laboratories also maintain larger reference collections and keep detailed case records.
Many organisations operate both: workstations at the points where documents are presented, and a central laboratory or external expert for referrals. The key is a clear referral route, so that a document that raises doubt at the workstation reaches the laboratory in the condition in which it was found. Equipment checks are covered in calibration and quality assurance. For a practical start, see setting up a questioned document examination position. See also: what is a questioned document? For spectral comparison, see what a video spectral comparator does. Our article on when to escalate covers that decision.
Frequently asked questions
What is forensic document examination?
It is the examination of documents to determine their authenticity, detect alterations, establish how they were produced and, in handwriting cases, identify the writer. It uses magnification, controlled light and comparison with reference material.
What is the difference between forensic document examination and document authentication?
Document authentication usually refers to checking whether an identity document or banknote is genuine, often at the first line. Forensic document examination covers that and more, including alterations, origin, writing and handwriting, and leads to a reported conclusion.
What equipment does a forensic document examiner use?
Magnifiers and microscopes, white light from different angles, ultraviolet and infrared light sources and cameras, image capture, and in laboratories spectral comparison and electrostatic detection instruments.
Is forensic document examination destructive?
The core methods are not. Magnification, oblique and transmitted light, UV and IR leave the document unchanged. Destructive methods such as ink sampling are used last and only where needed.
Who carries out forensic document examination?
Forensic document examiners in police and government laboratories and in independent practice. First-line checks are done by border officers, police, bank staff and notaries, who refer doubtful documents to an examiner.
Does forensic document examination include handwriting analysis?
Handwriting and signature comparison is part of the discipline, carried out by examiners trained specifically for it and based on comparison with known samples.
Equipment for forensic document examination
Dexeq supplies optical equipment for every stage of the examination sequence, from handheld magnifiers and UV lights to IR cameras, microscopes and desktop examination systems. Dexeq was founded in 2011 by a former officer of the Royal Netherlands Marechaussee with 18 years of service, 11 of them as a document fraud expert, and supplies more than 45 police and immigration agencies worldwide.
Browse the forensic examination systems, see the full product range, or request a quote for a workstation or laboratory setup.