Alterations: Erasures and Obliterations of Documents

Forensic document examiners (FDEs) are frequently tasked with the examination of a document to ascertain whether any erasures or entries have been altered, or to decipher any entries that have been overwritten and obscured.
- They employ a range of tools and lighting options to find alterations, obliterations, and erasures.
- The document's obverse and reverse sides are examined under natural lighting and low magnification (X5-X40).
- Visible light spectrum: The range of light wavelengths that the human eye can normally see.
- It is possible to identify, analyze, and restore questioned entries by using alternative wavelengths created by filters and light sources.
- Foster & Freeman Ltd. (UK) manufactures video spectral comparator (VSC) instruments that are used in institutions ranging from banks to full-service crime laboratories.
- Projectina AG is a Swiss company that produces a similar line of instruments known as the DocuCenter or Docubox.
- These tools give the examiner the ability to quickly and with a variety of wavelengths examine documents.
- It enables quick and simple documentation of the examination-related evidence.
- Fuji developed a UV/IR camera that enables an examiner to take direct digital pictures of effects visible in the UV and IR wavelengths.
- A promising analytical tool for ink comparison is Photoshop's LAB-Color Mode.
- Indented impressions in paper are discovered using electrostatic detection devices (EDDs).

Additive alterations are made by adding content to a document.
- Since the original entry involves perforating the check stock, this modification can only "raise" the amount of a check.
A visual inspection of a document's obverse side might reveal entries that aren't lined up.
Line crossings that don't occur in the expected order can indicate an alteration.
Oblique lighting is used to examine the reverse side of handwritten documents to see if there is any difference in the level of embossing from the obverse side.
If different fonts were used when typing a document, changes could be seen.
Using special grids can demonstrate that the contested text was added later if the alteration was made by adding text after it was initially typewritten.
E-ruler: A type of ruler used in the graphics industry, is the measurement tool for font size and interlinear spacing.
Toner: A resinous material that sits on the paper and gives it an embossed appearance.
Most ink-jet printers use liquid ink that soaks into the paper, some are solid inks. Tektronix introduced these in 1991.
Different "trash marks" left on copies produced by different photocopiers can sometimes distinguish them.
- These blemishes are caused by blemishes on the copying platen, rollers within the machine, the drum, and charging devices or cleaners.
Additional methods for ink differentiation include Raman spectroscopy, thin-layer chromatography, gas chromatography, and liquid chromatography.

Mechanical erasure: The entry is rubbed off using an abrasive substance.
- Graphite and clay are the main ingredients in the marking core of a regular black pencil.
- A pencil's hardness influences how simple it is to erase its line. A hard black pencil leaves a lighter trace while a soft pencil produces an intense black line with little pressure.
- Mechanical erasure entails rubbing an abrasive over the paper surface. This causes the paper fibers to be disturbed. This is easily seen with oblique light.
- Lycopode spores have also been shown to detect erasures.
- Excessive rubbing can wear down the fibers to the point where the paper in the erasure becomes almost translucent. Backlighting quickly reveals this effect.
- These erasures can also be found using UV light because the smooth paper and erased area will reflect light differently.
Chemical erasures: These are typically used to remove ink lines or commercial printing. Bleach, acetone, brake fluid, and other chemical mixtures are examples of solvents.
- Deciphering the original entries in many erasures is nearly impossible.
- Some of the entries can sometimes be recovered by examining the embossing on the back of the document caused by the tip of the pen.
- It's worth noting that when photocopies are examined, evidence of an erasure on the original may not be replicated on the copy.

An obliterated entry is obvious to a document reader. It can be done in haste or at leisure during the writing process.
Infrared reflectance (IRR) and infrared luminescence (IRL) examinations are frequently successful in filtering the obliterating ink to reveal the original.
The use of the ubiquitous correction fluid is a common method of obliteration.
Backlighting is usually enough to reveal the obliterated entry in the first instance.
In order to induce luminescence in the ink entry, infrared radiation and filters can be used.
The FDE must look for evidence of obliterations when inspecting a photocopy.
On a photocopy, it may be impossible to tell if someone has used correction fluid carefully. Some telltale signs include missing lines or characters in the obliterated area.