How does ESDA prove that a page in a contract or will has been substituted?

When a writer presses a pen onto a page, the impression indents not only that page but the pages below it on the writing surface. The ESDA-2 (Electrostatic Detection Apparatus by Foster + Freeman) humidifies the page, lays a thin Mylar film over it, applies a corona charge that concentrates in the indented furrows, then develops the latent image with negatively charged toner beads. If a page in a multi-page document does not carry indented impressions of the text that should logically be on the page above it, or carries impressions of different text entirely, that page has been substituted. ESDA reads impressions four to five pages deep.

Which Indian statutes govern altered cheques and tampered wills for the QD examiner?

Three statutes form the standard exam set. The Negotiable Instruments Act 1881 Section 87 makes any material alteration of a cheque or other negotiable instrument void against parties who did not consent. The Indian Succession Act 1925 Section 71 says that an alteration of a will is ineffective unless it is re-executed in the same manner as the will itself. The forgery offences sit in IPC Sections 463 to 465, now Bharatiya Nyaya Sanhita 2023 Sections 336 to 340. The expert opinion of the QD examiner comes in under Bharatiya Sakshya Adhiniyam 2023 Section 39, the successor to Section 45 of the Indian Evidence Act 1872.

Examination of Alterations: Erasures, Obliterations and Additions

UGC-NET Paper 2 Unit IX notes on detecting altered documents: erasures, obliterations, additions, oblique light, UV/IR, VSC-8000 and ESDA, with Indian case-law.

Last updated: 18 May 2026

Alterations are the highest-volume work that lands on a questioned-documents (QD) bench in India. The Government Examiners of Questioned Documents (GEQD) at Shimla, Hyderabad and Kolkata, plus the QD divisions of CFSL Chandigarh and the state FSLs, process a steady stream of altered cheques (the figure changed from 5,000 to 50,000), tampered wills (one beneficiary's name scraped off and another written in), back-dated agreements, page-substituted contracts, and altered school and land records. The exam-relevant skill set covers how to spot the alteration with non-destructive optical tools first, then escalate to instrumental examination on a Video Spectral Comparator (VSC) and an Electrostatic Detection Apparatus (ESDA), and finally write an opinion that survives cross-examination under the Bharatiya Sakshya Adhiniyam 2023.

The NTA syllabus, Paper 2 Unit IX, names this topic in one short line, but the MCQs span four examiner moves. Spot the alteration class (erasure, obliteration, addition). Pick the right light (oblique, transmitted, UV at 254 and 365 nm, IR reflectance and IR luminescence in the 760 to 1000 nm band). Know the instrument (VSC-8000 by Foster + Freeman, ESDA-2). Tie the finding to the right Indian statute (Negotiable Instruments Act 1881 Section 87, Indian Succession Act 1925, IPC Sections 463 to 465 now BNS 2023 Sections 336 to 340). This page walks through each move with the case anchors NTA likes to test.

Key terms

Alteration: Any change made to a document after its original execution, including erasure, obliteration, addition, substitution and overwriting. A material alteration changes the legal effect of the instrument.
Erasure (mechanical): Physical removal of writing by rubber, knife, scalpel blade, sandpaper or eraser. Disturbs paper fibres, thins the paper, and lifts the sizing and surface gloss.
Erasure (chemical): Removal of ink by bleaching or oxidising agents such as sodium hypochlorite, chloramine T, oxalic acid, potassium permanganate or hydrogen peroxide. Leaves a residual ghost image and disturbs paper fluorescence.
Obliteration: Covering over the original writing with overwriting, scribbling, ink smudge or correction fluid (Tipp-Ex, whiteout) so the underlying text is not visible to the eye.
Addition (interlineation, insertion): Fresh writing squeezed between lines, in margins, after the last entry, or in blank spaces left in the original document. Often shows different ink, pen, slant, pressure, baseline or spacing.
Overwriting: Tracing over an original stroke with a fresh stroke, usually to change a digit or letter. Detected by stroke thickness, hesitation, and ink-line crossing sequence.
IR luminescence: Excitation in the visible (450 to 600 nm) and detection in the near-IR (around 700 to 1000 nm). Two visually identical inks can luminesce differently under IR, exposing the alteration.
VSC-8000

Erasures: mechanical and chemical

Rubber and blade scrape fibres; bleach scrubs ink. Each leaves a different footprint.

An erasure removes writing rather than hides it. The QD bench splits erasures into two classes that NTA likes to test side by side.

Mechanical erasure. A rubber eraser, knife edge, scalpel blade, sandpaper or fingernail abrades the paper surface and lifts the ink along with the top fibres. The tell-tale signs are paper disturbance (raised, frayed or matted fibres), thinning (transmitted light shows a brighter patch where the paper is now thinner), loss of surface gloss and sizing, and smudged or broken adjacent strokes. The first move on the bench is oblique light at a low angle of 5 to 15 degrees, which throws long shadows from the disturbed fibres and makes the erased area jump out. Transmitted light (sandwich the document on a light box) shows thinned paper as a bright halo. A low-magnification stereomicroscope at 10x to 40x then confirms fibre disturbance and any residual ink fragments inside the erasure.

Chemical erasure (ink eradication). Sodium hypochlorite (household bleach), chloramine T, oxalic acid, potassium permanganate followed by oxalic acid (the classic two-step), and hydrogen peroxide bleach the dye out of the ink. The paper fibres usually survive, but the sizing and the optical brighteners (OBA) that paper mills add to most cheque and bond paper are also bleached. The signature finding is a dark or non-fluorescent patch under long-wave UV (365 nm) where the surrounding paper glows bright blue-white from the OBA. Short-wave UV (254 nm) can show the same patch differently. IR reflectance often picks up a faint ghost image of the original carbon-rich pigment that the bleach did not fully destroy. Spot tests on tiny scrapings (potassium iodide, sodium nitrite, ammonia vapour) confirm the bleach class but are destructive and used sparingly. In India, the NI Act 1881 Section 87 treats a chemical alteration of the amount on a cheque as a material alteration that voids the instrument unless every party assents, which is exactly why this evidence is so often litigated.

Workflow on a VSC-8000 for a suspected erasure: visible white-light photograph at normal incidence, oblique light from four directions, transmitted light, long-wave UV at 365 nm, short-wave UV at 254 nm, IR reflectance from 715 to 1000 nm, then IR luminescence with visible excitation and IR detection. The sequence is non-destructive, repeatable, and documents the disturbance for the court file, mirroring the broader

Obliterations: overwriting, smudge and correction fluid

The original is still there under the cover. IR sees through what visible light cannot.

An obliteration hides the original instead of removing it. Three sub-classes show up in casework: overwriting (a fresh stroke laid on top), ink smudge or scribble (a heavy blot of ink masking the entry), and correction fluid (Tipp-Ex, Liquid Paper, Fevicryl whiteout) painted over the entry. The decoding rule is simple: choose the imaging band where the covering material is transparent or differently responsive while the underlying ink still absorbs.

Infrared reflectance (760 to 1000 nm). Most blue and black inks, including iron-gall and carbon-based pigments, absorb strongly in the near-IR and stay dark. Many dyes used in highlighters, modern ballpoint inks of pale colour, and the titanium-dioxide pigment in correction fluid become essentially transparent or weakly reflective in the IR. Image the document on the VSC-8000 with an IR camera and a long-pass filter starting around 715 nm and the obliterating layer often vanishes, exposing the original entry below. This is the single most-tested NET fact on this topic.

IR luminescence. Excite with visible light (typically 450 to 600 nm bandpass) and detect in the IR (above 700 nm). Two inks that look identical to the eye, say two black ballpoints used in an alteration, can luminesce very differently in the IR because their dye chemistry differs. The added stroke lights up bright while the original stays dark, or the reverse. This is how a single examiner can prove that two black strokes on a cheque came from two different pens without any chemical test.

Differential ink response. Even visible-light filtering on the VSC (Wratten 25 red filter, 47 blue filter, narrowband sets) often separates blue-black iron-gall ink from blue dye ink. Spot tests and thin-layer chromatography (TLC) confirm ink composition where non-destructive imaging is equivocal, but these consume material and are not run as the first step. The non-destructive IR-first protocol mirrors the discipline laid out in specialised photography (UV/IR/close-up)

Additions: interlineations, insertions and substitutions

What looks like one entry was written on two different occasions.

An addition is fresh writing slipped into a document after the original was executed. Five sub-classes form the casework set: interlineation (writing squeezed between two existing lines), insertion (a digit added to a figure, a zero added to 5,000 to make 50,000), interpolation (a word or clause inserted in a sentence), margin or after-the-last-line addition (a P.S. or a fresh paragraph), and page substitution (one or more sheets of a multi-page will, agreement or affidavit swapped out).

The examiner reads the document for internal inconsistency: change of slant (forward sloping to upright), change of pen pressure (light to heavy, visible as ridge depth under oblique light), change of baseline (the inserted word floats above or dips below the line of the surrounding text), change in spacing (the added digit is crowded against its neighbours because the writer ran out of room), change in ink colour or shade, change of pen type (ballpoint versus gel versus fountain pen), and change of writing implement angle (broader or finer stroke). On the VSC-8000, the same IR reflectance and IR luminescence bands that catch obliterations also catch additions because the second ink rarely matches the first ink exactly across all wavelengths.

Page substitution in a multi-page contract or will is the hardest variant and is where ESDA earns its keep. When a writer presses a pen onto page one, the impression goes through and indents pages two and three below. Develop the indented impressions on each page with the ESDA-2: a thin polymer film is laid over the document, charged with corona, then dusted with toner that sticks to the indented furrows. If page two carries indented impressions of text that does not appear on page one, page one has been substituted. The same technique recovers indented impressions of cheque numbers, addresses and dates from the page below a writer's pad, a routine output of the QD division at GEQD Shimla.

Sequence of strokes. When an addition crosses an original stroke (a "1" turned into "7" by adding a horizontal bar that crosses the vertical of the 1), the upper, lower or interrupted nature of the crossing tells the order. Stereomicroscopy at 40x to 80x, oblique-light micrography, and lift techniques (gelatin lift, polysulphide cast) all answer the sequence question.

VSC-8000 examination flow and ESDA

One instrument runs the optical menu; ESDA reads the impressions left behind.

The Video Spectral Comparator VSC-8000 by Foster + Freeman is the workhorse of QD divisions at CFSL Chandigarh, GEQD Shimla, GEQD Hyderabad, GEQD Kolkata and most state FSLs in India. A typical examination flow runs in eight steps. (1) Capture a high-resolution visible-light reference image at normal incidence with calibrated colour. (2) Switch on oblique side-lighting from four cardinal directions to image fibre disturbance, indented furrows and surface gloss loss. (3) Drop the document onto the transmission stage for thinning and watermark imaging. (4) Long-wave UV at 365 nm to image OBA loss and security-feature response. (5) Short-wave UV at 254 nm to image dye-class differences. (6) IR reflectance from 715 to 1000 nm to see through obliterations. (7) IR luminescence with visible excitation and IR detection to separate visually identical inks. (8) Spot-filter combinations and side-by-side comparison of the questioned and known entries. Each image is logged with date, time, examiner ID, wavelength, exposure and the document's reference number, building the chain-of-custody trail the BSA 2023 admissibility framework expects.

The Electrostatic Detection Apparatus ESDA-2, also Foster + Freeman, is non-destructive: the document is humidified in a closed cabinet, sandwiched under a thin Mylar imaging film, charged by corona with the indented furrows attracting more charge, then developed by cascading negatively charged toner beads across the film. The resulting image is fixed onto an adhesive sheet for the case file. ESDA reads indented impressions four or five pages deep and is the standard tool to detect rewritten cheque amounts, missing pages in multi-page wills and contracts, and the presence of writing-pad transfers in extortion notes and ransom letters.

Indian case-law and casework

Cheques under NI Act 87, wills under the Succession Act, forgery under the BNS.

Negotiable Instruments Act 1881, Section 87 (material alteration). Any material alteration of a negotiable instrument made without the consent of all parties liable on it renders the instrument void as against them. Adding a zero to change 5,000 to 50,000, or changing "Pay to A" to "Pay to B", is the textbook material alteration. The QD opinion that establishes the alteration becomes the spine of the civil suit and any IPC/BNS prosecution.

Indian Succession Act 1925. A will altered after execution carries no effect unless the alteration is executed in the same manner as the will itself (signed and witnessed afresh, Section 71). Erasure of a beneficiary's name and insertion of another, common in disputed estate matters, lands at GEQD Shimla and CFSL Chandigarh. The ESDA test for indented impressions of an original page often settles the question.

IPC Sections 463 to 465, now BNS 2023 Sections 336 to 340. Forgery, making a false document and using a forged document attract the criminal prosecution. The QD report establishing alteration is the prosecution's expert evidence under BSA 2023 Section 39, the successor to Section 45 of the Indian Evidence Act 1872.

Murari Lal v. State of MP (1980, Supreme Court). Long-standing authority that the opinion of a handwriting and document expert is relevant under what was Section 45 IEA (now BSA 2023 Section 39), and that the court can act on it provided the reasoning is laid out and the expert can withstand cross-examination. NTA asks this case as the foundational reference for QD expert admissibility.

Daulat Ram Saini v. State of Rajasthan and the long line of cheque-alteration cases. Indian courts routinely admit VSC-based QD opinions on tampered cheques, with the examiner's photographs and wavelength logs forming the exhibits. Defence counsel attacks chain of custody, the qualifications of the examiner, and the absence of comparison standards; the examiner's clean chain of custody and a documented non-destructive workflow defeat most of these attacks.

MCQ takeaways

Three alteration classes: erasure (mechanical or chemical), obliteration (overwriting, smudge, correction fluid), addition (interlineation, insertion, page substitution).Oblique light angle: 5 to 15 degrees, for fibre disturbance and indented impressions.UV bands: 254 nm (short-wave) and 365 nm (long-wave). Bleached patches lose OBA fluorescence under 365 nm.IR reflectance band: 760 to 1000 nm; IR luminescence excitation 450 to 600 nm, detection above 700 nm.Correction fluid (Tipp-Ex, titanium dioxide) is opaque to visible light but largely transparent to IR around 900 to 1000 nm.VSC-8000 is by Foster + Freeman, standard in CFSL Chandigarh, GEQD Shimla, Hyderabad and Kolkata.ESDA-2 is by Foster + Freeman; reads indented impressions four to five pages deep.NI Act 1881 Section 87: material alteration of a negotiable instrument voids it without consent of all parties.Indian Succession Act 1925 Section 71: alteration of a will is ineffective unless re-executed in the same manner as the original.IPC 463 to 465 = BNS 2023 Sections 336 to 340 for forgery; expert opinion comes in under BSA 2023 Section 39.

How do you tell a mechanical erasure from a chemical erasure on a cheque?

Run the cheque through the optical menu on a VSC-8000. Mechanical erasure (rubber, knife, sandpaper) shows fibre disturbance under oblique light at 5 to 15 degrees and a bright thinned halo under transmitted light, because the surface fibres have been physically lifted. Chemical erasure (sodium hypochlorite, chloramine T, oxalic acid) usually leaves the fibres intact but bleaches the optical brighteners in the paper, so the treated area appears as a dark non-fluorescent patch under long-wave UV at 365 nm while the surrounding paper glows bright blue-white. A faint ghost image of the original entry often remains visible in IR reflectance.

Why does infrared light see through correction fluid and ink obliterations?

The covering material in correction fluid (titanium dioxide pigment) is opaque to visible light but largely transparent to near-infrared around 900 to 1000 nm. Most blue and black inks, on the other hand, absorb strongly in the near-IR and stay dark. Imaging the document with an IR camera and a long-pass filter above 715 nm therefore makes the white cover effectively vanish while the original ink stroke underneath still reads. The same principle works for many ink-over-ink obliterations because two inks of the same visible colour can have very different IR absorption.

What is the difference between IR reflectance and IR luminescence on a VSC-8000?

IR reflectance illuminates the document with broadband IR light and images the IR reflected back; it relies on absorption differences between the two inks or between ink and cover. IR luminescence illuminates with visible light (typically 450 to 600 nm) and images only the IR that the inks themselves emit (above 700 nm); it relies on dye fluorescence differences. The two techniques are complementary and the VSC-8000 runs both as routine steps in an alteration examination.

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