# Detect tampered and deepfake Cheque > Cheque fraud has a vocabulary of its own because the instrument is old enough to have been attacked every way there is. The dominant method is washing: a genuine signed cheque is lifted from the post, the payee and amount are chemically or digitally removed, and new ones are written in. The signature is real, the account is real, the stock is real, and only two fields are false. TamperCheck reads the background pattern that the removal disturbed. **Canonical URL:** https://tampercheck.ai/documents-support/cheque **API document class:** `cheque` **Last updated:** 2026-10-07 --- ## What a genuine cheque contains A cheque is a payment instruction printed on security stock. It carries the drawer's name and the bank's branch details, a cheque number, the date, the payee line, the amount written twice, once in figures in a boxed field and again in words across the body, and the drawer's signature. Along the foot runs the MICR line in magnetic ink: cheque number, sort code or routing number, and account number, set in a fixed character shape. Beneath all of it lies a guilloche, a fine engraved background pattern. Writing the amount twice is the oldest anti-tamper control in banking, and it still works: figures and words have to agree, and an edit to one leaves the other describing a different payment. The cheque number appears twice as well, printed at the top and encoded in the MICR line, so the two have to match. The guilloche runs continuously beneath the printed fields, which means anything erased, bleached, or pasted over the payee line interrupts a pattern that has no business being interrupted. ## How cheque forgeries are made ### Cheque washing The payee and amount are removed from a genuine signed cheque with solvent, or erased from a scanned image, and rewritten in favour of the fraudster. Solvent leaves the fibres and the engraved background degraded around the cleared area, while digital removal interrupts the same pattern along an unnaturally clean edge. ### Amount raising The figure in the boxed field is increased and the written amount is left alone, or both are changed and only one is convincing. Banks pay on the written amount for exactly this reason, and a mismatch between words and figures is the single most reliable contradiction the instrument offers. ### Overlay on a deposit image Cheques are now deposited as photographs, so the attack has moved to the image. A new payee name or amount is composited onto the capture and tone-matched to it. The overlaid region carries its own sharpness and compression signature and does not share the lighting gradient falling across the paper. ### Signature forgery The drawer's signature is traced, scanned from another document, or printed rather than written. A printed signature has uniform ink density and no pressure variation, and a pasted one sits above the guilloche instead of crossing through it, which shows in how the two layers interact. ### MICR line tampering The account or routing digits along the foot are reprinted so an instrument draws on a different account, or routes slowly enough to clear before it is returned. MICR characters have a fixed shape and spacing, and reproduced ones rarely match the geometry of the set they sit in. ### Counterfeit stock Entire cheques are printed on plain paper against an account number harvested from a genuine one. The giveaway is the substrate rather than the data: a reproduced guilloche loses its fine line structure when it is scanned and reprinted, and border microprint collapses into a grey smear. ## What TamperCheck checks on a cheque TamperCheck runs 200+ forensic checks across three layers and returns a risk score from 0 to 100 with plain-English findings tied to specific regions of the document. These three carry the most weight on this document class. ### Security print, foil, and hologram analysis A genuine security overlay or guilloche background behaves differently from a printed picture of one. A reproduction loses the structure that made the feature a security feature in the first place, and that loss is measurable even when the copy looks convincing on screen. ### Arithmetic reconciliation Stated totals are recomputed from their components, and running or cumulative figures are checked for continuity across periods. A single edited value breaks the chain even when the page still looks right. ### Signature forgery analysis Signature regions are assessed for ink consistency and for how the stroke sits on the page, which distinguishes a genuine pen stroke from a pasted image of one. ### And many more checks The three above are the layers that carry the most weight on a cheque. Every upload runs the full suite of 200+ checks regardless of document class, spanning file structure and metadata, pixel-level forensics, font and text rendering, optical and print characteristics, provenance signals, AI-generation signatures, and many more checks. ## Who verifies a cheque, and why Banks and treasury teams clearing payment instruments. In each case the document is being used to unlock money, access, or a legal status, which is exactly what makes it worth forging. ## How to verify a cheque in 4 steps 1. **Check the fields against each other.** Read payee name, amount in figures and words, and drawer signature together rather than one at a time. Forgers typically change one value and leave the rest of the document describing the original. 2. **Inspect the file metadata.** Open the document properties and look at the producer, creation date, and modification date. A document produced by a consumer PDF editor, or created long after the date printed on its face, is worth a closer look. 3. **Ask for a second document.** Request a corroborating document from the same issuer or an adjacent period. Forgery effort concentrates on one file, so inconsistencies surface as soon as there are two to compare. 4. **Run a forensic check.** Manual review catches obvious edits but not field-level pixel manipulation or synthetic generation. TamperCheck runs 200+ forensic checks on a cheque and returns a risk score from 0 to 100 within seconds, at $0.50 per document. ## Frequently asked questions ### How do banks detect altered cheques? Banks detect altered cheques by testing the instrument's built-in redundancy: the amount in words against the amount in figures, the printed cheque number against the MICR line, and the signature against the account mandate. On deposit images they add image forensics, because the cheque now arrives as a photograph. TamperCheck runs the same class of checks on any cheque image and returns findings tied to specific regions. ### What is cheque washing and how is it caught? Cheque washing is the removal of the payee name and amount from a genuine signed cheque so they can be rewritten in favour of someone else. Chemically it is done with solvent, which damages the paper fibres and the printed background around the cleared field. Digitally it is done on a scan or a deposit photograph, which breaks the guilloche pattern along an edge too clean to be wear. ### Can a cheque photographed for mobile deposit be edited? Yes, and it is now the more common method. A deposit capture is an ordinary photograph, so a payee name or an amount can be composited onto it in any image editor and matched for tone. The edited region keeps a different sharpness profile and compression history from the rest of the image, which per-field analysis isolates and names. ### How do I tell if a cheque is counterfeit? Look at the background pattern and the border microprint before anything else. A genuine guilloche holds continuous fine lines and microprint resolves into readable characters under magnification, while a scanned and reprinted cheque turns both into grey mush. Then confirm the stock feels like security paper and that the MICR line is printed in magnetic ink rather than ordinary toner. ## Related document types - Invoice: https://tampercheck.ai/documents-support/invoice - Receipt: https://tampercheck.ai/documents-support/receipt - Purchase Order: https://tampercheck.ai/documents-support/purchase_order - Proposal: https://tampercheck.ai/documents-support/proposal - Quotation: https://tampercheck.ai/documents-support/quotation - Wire Transfer: https://tampercheck.ai/documents-support/wire_transfer --- Try TamperCheck now: https://tampercheck.ai/dashboard · Docs: https://tampercheck.ai/docs · Pricing: https://tampercheck.ai/pricing