Passport security features are built in layers: the substrate (paper or polycarbonate), the printing, the personalisation of the holder’s data, optically variable and protective elements, and in an ePassport a chip. To check them, you inspect each layer with the light and magnification it was designed for (white, oblique, transmitted, UV and infrared light, and a magnifier) and compare what you see with a genuine reference of the same passport type and version.
This guide goes through those layers one by one: what each feature is, how to check it, and which tool you need. It is written for first and second-line inspection at border posts, immigration desks, banks and other counters where passports are presented. For the full range of equipment by task, see document authentication equipment.
How passport security features are organised
Security features are usually grouped by who can check them. First-line features can be verified by eye, by touch and by tilting the document, without tools. Second-line features need a simple tool: a UV flashlight, a magnifier, transmitted light or an infrared camera. Third-line features are verified in a forensic laboratory with specialised equipment and reference material.
A genuine passport combines features from all three levels, and from several of the layers below. A forger may reproduce one feature well, but reproducing all of them consistently is much harder. That is why a check should never rely on a single feature: the strength of the passport is in the combination.
The international baseline for the design of passports is ICAO Document 9303, which sets the layout of the data page and the machine readable zone and describes the security of the design. The features below are common to most modern passports, but each issuing state chooses its own combination, so a reference for the specific passport is always needed. More on the standard in ICAO 9303 explained for document inspectors.
The substrate: paper and polycarbonate
The visa pages of a passport are security paper. The data page is either the same paper, protected by a laminate, or a polycarbonate card bound into the booklet. The substrate carries its own features, made during manufacture of the material.
- Watermark. A design created in the paper itself by varying its thickness. In transmitted light it shows light and dark tones; it cannot be seen in reflected light in the same way. Check by holding the page against a light source. See transmitted light: verifying watermarks and see-through features.
- Security fibres and planchettes. Coloured fibres or small discs embedded in the paper, often visible only under UV. They are distributed at random and lie in the paper, not on it. Check under a 365nm UV flashlight and with a magnifier.
- UV-dull paper. Security paper is made without optical brighteners, so it stays dull under UV while ordinary paper glows blue-white. A page that lights up as a whole under UV is a strong warning sign.
- Security thread. A thin strip embedded in the paper, sometimes with text, visible in transmitted light and often fluorescent under UV.
How substrate and print are made is described in substrate and print: how a secure document is made.
Printing: background, microprint and special inks
The printed design of a passport page is a security feature in itself. Security printers use techniques and inks that office printers and most commercial printers cannot reproduce.
- Background printing. Fine line patterns such as guilloches and rainbow printing, where colours merge without a visible dot structure. Under a magnifier the lines of a genuine print are continuous and sharp. See guilloche and rainbow printing.
- Microprinting. Text so small that it looks like a line to the naked eye. At 10x you see that it is text; at 15x you can read it. A copy turns microprint into dots or a blurred line. See microprinting: how to inspect micro- and nano-print.
- Intaglio printing. Raised ink that can be felt and that casts small shadows in oblique light. Check by touch and with a light held low over the page.
- UV and IR inks. Inks that are invisible in daylight and light up under UV, or that respond to infrared in a defined way. Check under a UV flashlight and an IR camera, against the reference.
- Colour-shifting ink. Optically variable ink that changes colour when the page is tilted.
Personalisation: the holder’s data
The data of the holder is added to the passport after manufacture. Most attacks on genuine passports target this layer, by changing the data or replacing the portrait, so it deserves the most attention.
- Laser engraving. On a polycarbonate data page, the portrait and the data are engraved inside the material with a laser. The engraving is part of the card and cannot be removed without damaging it. In oblique light, raised areas or a tactile element can often be seen; in infrared, laser-engraved data stays dark because it is carbon in the material.
- Ghost image. A second, smaller portrait of the holder, often printed in a lighter tone or in UV ink. It should match the main portrait.
- Laser perforation. The document number or a portrait perforated through the pages or the data page. Check in transmitted light: the holes should be clean and the number should match the data page.
- The machine readable zone. Two lines of characters at the bottom of the data page that repeat the key data with check digits. A mismatch with the visual zone is objective evidence. See passport MRZ: how to check the machine readable zone.
Optically variable and protective features
Most data pages are protected by a laminate or overlay with an optically variable device (OVD), such as a hologram or kinegram, that changes when the page is tilted. Some passports use a retroreflective laminate with a pattern that becomes visible only in coaxial light, such as with a 3M Retroviewer.
Check that the OVD moves and changes as expected when tilted, that it sits where the reference shows it, and that its edges are clean and not lifted. How these elements look under magnification is covered in spotting OVD security features with a 10x magnifier and security features that depend on viewing angle.
The ePassport chip
An ePassport carries a contactless chip with the holder’s data and portrait, marked on the cover with the ePassport symbol. Reading and verifying the chip needs a reader and the right certificates; a manual inspection cannot confirm what is on the chip. What a physical check can do is confirm that the symbol is present where it should be, and that the booklet shows no signs of the chip area being opened or replaced.
Which tool for which passport security feature
| Feature | How to check | Tool |
|---|---|---|
| Watermark, security thread, laser perforation | Transmitted light | Magnifier with transmitted light, or a light source behind the page |
| Fibres, UV inks, UV-dull paper | 365nm UV light, compared with the reference | UV flashlight or illuminated magnifier |
| Microprint, background printing, edges of the portrait | 10x to detect, 15x to read | Handheld magnifier |
| Intaglio, tactile features, engraving relief | Oblique light and touch | Magnifier with oblique light |
| IR inks, laser-engraved data | Infrared light | IR camera |
| Hologram, kinegram, colour-shifting ink | Tilting under white light | No tool needed; a magnifier for detail |
| Retroreflective laminate | Coaxial light | 3M Retroviewer or a magnifier with coaxial light |
A checking sequence for the data page
- Look at the whole page in white light: layout, fonts, alignment, the portrait and its edges.
- Tilt the page: the OVD and colour-shifting elements should change as expected.
- Feel the page and look in oblique light for relief and tactile elements.
- Hold the page against a light: watermark, thread and perforations.
- Switch to 365nm UV: paper response, fibres, UV inks.
- Use a magnifier on the microprint, the background and the portrait edges.
- If available, check in infrared.
- Compare the machine readable zone with the visual zone.
A finding at any step is a reason for a closer look, not yet a conclusion. When a passport has to go to second line, see when to escalate a document to second line.
Frequently asked questions
Watermarks, security fibres and threads in the substrate; guilloche and rainbow background printing, microprinting, intaglio and UV and IR inks in the print; laser engraving, a ghost image, laser perforation and the machine readable zone in the personalisation; an OVD or retroreflective laminate on the data page; and in an ePassport a contactless chip.
Work through the data page with white, oblique and transmitted light, a 365nm UV flashlight, a 10x to 15x magnifier and, if available, an IR camera, and compare each feature with a genuine reference. Check the machine readable zone against the visual zone. Only the chip needs a reader.
Features that need no tools or only simple ones: the layout, the OVD when tilted, intaglio relief by touch, the watermark against the light, the UV response under a UV flashlight, and the machine readable zone against the visual zone.
A forger may reproduce one feature convincingly. Reproducing all features of a passport consistently is much harder, so the reliability of a check comes from combining several features from different layers.
