Detecting Alterations in Documents

An alteration is the unauthorized modification of a security document and can occur for a variety of reasons.

Financial documents are altered for obvious reasons and include checks, wills, deeds, trusts, and stock certificates.  Other documents are altered for the free movement of people like passports and visas.  Still other documents are altered to gain benefits like health care forms, child custody agreements, employment contracts, and social security cards.

Alterations of financial documents such as checks and stock certificates are frequently examined by document examiners.  Personal checks are altered by using a similar type of writing ink and raising the dollar amount and adding words to the written entries.  Another option is check washing: where a check will be intercepted, washed and presented as a legitimate check.  Detection of these types of alterations may be done by examining the check under alternate light sources such as ultraviolet and infrared.  These light sources can show a reaction in the paper that a chemical was applied or that a different pen was used to raise the dollar amounts on the checks.  With stock certificates, alterations may occur with the typewriting or printing process used to produce the certificate.  Often the alteration will demonstrate a style of typewriting/printing that is not consistent with the rest of typewritten/printed certificate or a printing process that was not commercially available when the stock certificate was issued.  All of these characteristics must be carefully analyzed and a conclusion based on the entirety of the document.

Identity and security documents such as passports, visas, and driver’s licenses are targets for alterations as well.  Alterations to a genuine document like a passport may include photo substitutions, page substitutions, mechanical and chemical erasures.  Photo substitutions is the most common form of passport fraud.  The photograph of the original owner is removed and a new photograph put in its place.  Information that cannot be easily altered or erased is removed by disassembling the passport, removing the page of unwanted data (visa denial), and reassembling the page with a genuine page from another passport or replacing with a counterfeit page.  Printed and written information can be altered by mechanical or chemical erasures.  An erasure may be whole word, letters, portions of letters, or dates.  Chemicals used to erase information can be detected with ultraviolet light.


Detecting alterations depends on specialized equipment, light sources, and microscopes like the stereomicroscope and comparison microscope. One piece of specialized equipment used to detect alterations is a multi-spectral imaging device.  This device allows a document examiner to perform non-destructive testing with specialized lights sources and filters  covering the visible, ultraviolet, and infrared range of light. This equipment is the workhorse of any document examiner’s office and assists with analyzing a variety of materials including substrates, printing, laminates and holograms.

Other equipment such as side lighting or oblique lighting can detect indented impressions.  Detecting indented impressions on paper can provide valuable information to the examiner such as the sequencing of entries in a journal.  This may be helpful when working on medical record alterations of a patient’s chart or doctor’s notes, ledgers used for recording daily transactions, checkbooks, or notebooks.


A stereomicroscope provides magnifying power to allow fine details of a document to be observed.  Combined with lighting options, this can be particularly useful for distinguishing printing processes, detecting indented impressions, to observe handwriting features, and identifying security features like microprinting. These observations are recorded in the examiner’s notes or captured with a camera that may also be mounted on the microscope.


Lastly, a comparison microscope involves the use of two compound microscopes providing a split screen for an examiner to compare two things side-by-side.  These are especially useful for typewriting cases in discovering defects and non-print area or for any examination where a detailed side-by-side examination would be beneficial.  For alterations of passports, for examples, it may be useful to review the genuine passport alongside the suspect passport to determine all the security features and anomalies.


Detecting alterations is reliant on good training and equipment. Being able to recognize the characteristics of genuine features will help immensely when detecting alterations in security documents.