ClearText®
De La Rue (United Kingdom)
Type: Demetallised windowed security thread — woven into banknote paper substrate, appearing as a windowed thread integrated during papermaking
Overview
ClearText® is one of De La Rue's longest-established and most widely deployed security thread technologies, and one of the most recognisable thread formats in the history of banknote security. Introduced in windowed form in 1990, it became highly successful with rapid adoption across many currencies worldwide, and remains in active circulation on numerous denominations decades after its introduction. The thread was developed as part of the same programme of innovation at De La Rue that produced the world's first windowed thread banknote — the Bank of England series D £20 note in 1984 — and represents the demetallised evolution of that windowed thread concept. Its longevity is a testament both to its counterfeit resilience and to the public familiarity it has built over more than three decades of circulation. ClearText® also functions as an enhancement layer within De La Rue's more advanced thread technologies — including STARCHROME®, KINETIC STARCHROME®, and IGNITE® — where it provides denomination-specific demetallised text as a secondary authentication element. In DataVault, ClearText® as a standalone brand refers exclusively to banknotes where the primary embedded thread technology is the demetallised windowed thread without any additional colour-shift, holographic, or micro-optic layer.
Technology & Effects
ClearText® is constructed from a metallised polymer substrate — typically polyester — in which characters, numerals, or patterns are selectively removed from the metallic layer through a demetallisation process. The resulting thread presents differently depending on the viewing condition: under normal reflected light, the thread appears as a continuous metallic line, largely indistinguishable from a standard metallic thread and contributing minimally to the surface design. When the banknote is held up to a transmitted light source — a window, lamp, or light box — the demetallised regions become transparent, causing the characters or patterns to appear as bright, readable text or imagery against the dark metallic background of the thread. This transmitted-light effect is both intuitive and highly distinctive: the text or denomination numeral is immediately legible to the public without any tools beyond a light source, and the presence of clear, sharp text within the thread is impossible to replicate convincingly using standard printing or foil-blocking counterfeiting techniques. The thread can incorporate positive demetallisation — where the characters are formed by the clear regions — or negative demetallisation, where the characters are formed by the remaining metal, giving designers flexibility in the visual appearance of the text. Optional enhancements include UV fluorescence and magnetic machine readability, adding Level 2 and Level 2b authentication layers to the base Level 2a teller-assist functionality provided by the transmitted-light text.
Form Factors & Application
ClearText® is woven into the banknote paper during manufacture as a windowed security thread, surfacing at regular intervals across the face of the note in the characteristic windowed format first developed by Portals for De La Rue in the early 1980s. Thread width, window pattern, and character content are customised for each denomination and issuing authority, with denomination numerals or central bank initials most commonly incorporated as the primary demetallised content. The thread is durable and maintains its transmitted-light authentication effect throughout the full circulation life of the banknote. It is compatible with a wide range of paper mills and substrate configurations, and has been manufactured for state printworks as well as commercial printers globally.
Security Levels
ClearText® operates primarily as a Level 2a (teller-assist) authentication feature. The transmitted-light text is not immediately visible under normal reflected-light viewing conditions — a deliberate design choice that reserves this verification layer for trained cash handlers and tellers who routinely hold notes to the light, rather than relying on the general public to perform an active check. In practice the windowed thread itself — the alternating appearance and disappearance of the metallic strip across the face of the note — functions as an additional Level 1 (public) cue, as the windowed format is well-established as a genuine note characteristic and is difficult to simulate convincingly by printing alone. Optional magnetic encoding extends authentication to Level 2b automated machine verification.
| Security Feature | Banknotes |
|---|---|
| 309 | Thread | Embedded | Narrow | Machine readable magnetics | Cleartext | 2 |
| 20 | Thread | Embedded | Narrow | Demetallised & Machine readable magnetics | Cleartext | 18 |
| 10 | Thread | Back | Embedded | Wide | 2.5mm | Registered | Demetallised & Machine readable magnetics | Cleartext | 6 |
| 323 | Thread | Embedded | Wide | 2mm | Demetallised & Machine readable magnetics | Cleartext | 1 |
| 216 | Thread | Front | Windowed | Narrow | Demetallised | Cleartext | 65 |
| 159 | Thread | Back | Windowed | Wide | 2mm | Demetallised | Cleartext | 7 |
| 310 | Thread | Embedded | Narrow | Demetallised & Machine readable magnetics | Cleartext & Magnetic code | 10 |
| 221 | Thread | Front | Windowed | Wide | 2mm | Demetallised | Cleartext | 2 |
| 194 | Thread | Back | Windowed | Wide | Demetallised | Cleartext | 4 |
| 286 | Thread | Front | Windowed | Wide | Demetallised | Cleartext | 8 |
| 211 | Thread | Front | Windowed | Narrow | 1.2mm | Demetallised | Cleartext | 4 |
| 163 | Thread | Back | Windowed | Wide | 3mm | Demetallised | Cleartext | 1 |
| 306 | Thread | Embedded | Narrow | 1.5mm | Demetallised | Cleartext | 7 |
| 156 | Thread | Back | Windowed | Narrow | Demetallised | Cleartext | 25 |
| 212 | Thread | Front | Windowed | Narrow | 1.4mm | Demetallised | Cleartext | 4 |
| 303 | Thread | Embedded | Narrow | 1.2mm | Demetallised | Cleartext | 1 |
| 311 | Thread | Embedded | Narrow | Demetallised | Cleartext | 66 |
| 215 | Thread | Front | Windowed | Narrow | Demetallised & Machine readable magnetics | Cleartext | 5 |
| 14 | Thread | Embedded | Narrow | 1.5mm | Demetallised & Machine readable magnetics | Cleartext | 6 |
| Total Unique Banknotes | 242 |
- Name
- ClearText®
- Category
- Security Feature
- Effect Types
- Demetallised
- Company
-
De La Rue
Company Website - Product Page
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