Questions we get asked before a specification is written

Tamper evidence is a feature designed so that opening or interfering with a pack leaves a visible, permanent change — usually a hidden VOID message that appears in the label, on the surface, or both.

Its purpose is detection and deterrence, not physical resistance. A seal cannot prevent someone opening a box; it means the next person to handle it can tell that it was opened.

The void, or hidden security message, is printed within the construction and is invisible while the label or tape is intact. When the material is lifted, the layers separate and the message is revealed — either in the label itself (non-residue) or transferred onto the packaging surface (total transfer).

Once a void has been triggered, the material cannot be returned to its original undisturbed appearance. Some attacks — solvents, heat, cold, careful slow peeling — are specifically what the higher-specification constructions are designed to reveal, which is why the attack methods you expect matter when specifying.

Overt features are meant to be seen: printed VOID messages, bold colours, obvious security graphics. They deter interference and let untrained handlers spot a problem.

Covert features are hidden and used for checking: UV inks visible only under a blacklight, sub-surface print, or covert patterns known only to your team. Most specifications combine both — overt for the supply chain, covert for verification at receipt.

No, and the distinction matters. Tamper evidence tells you whether a pack has been opened or interfered with since it was sealed. Authentication tells you whether an item or its packaging is genuine.

They are often combined — for example a tamper-evident label carrying unique numbering, a barcode or a covert UV feature that can be checked against your records — but a void message on its own does not prove origin, and an authentication feature on its own does not show that a pack was opened.

Interference becomes visible at the point of receipt, disputes about where a loss happened become answerable, and the presence of a specialist seal discourages opportunistic interference.

What it will not do on its own: stop a determined, well-resourced attack, replace physical security, or guarantee a percentage reduction in loss. Any figure like that depends on your process, not on the label.

Almost always in one of four places: the surface (low-energy plastics, powder-coated metal, recycled board and dusty or oily surfaces resist adhesion), the temperature at application or in transit, the handling (abrasion, moisture, stacking pressure), or the process — nobody is checking the seal on arrival.

The last one is the most common. Tamper evidence only works when someone is required to look at it and record the result.

Non-residue constructions reveal the void within the label and lift away without leaving adhesive or message behind. Use them where the surface must stay clean and reusable: aircraft doors, trolleys, equipment, vehicles, returnable assets.

Total transfer constructions leave the void message on the packaging surface as well as in the label. Use them on single-trip cartons, bags and consumables, where evidence left on the pack itself is an advantage.

• X22 — the standard, most versatile non-residue label. The hidden security message appears within the label on removal and cannot be reinstated to its original appearance.
• X22FU — a specialist version that also indicates the method of attack, with security cuts and differing reactions to solvent and heat.
• X2005 — non-residue with an outline void, designed for high surface energy materials such as vehicle panels and fuel pumps, leaving no residue on removal.
• X22G UV — clear non-residue gloss with UV ink that fluoresces under a blacklight, for covert checking.

Suitability always depends on the surface and temperature at application. Sample testing on your own pack is the only reliable confirmation.

• PL — total transfer permanent labels. Designed so that attempted removal reveals a clean dry-peel security message and transfers it to the surface; they cannot be lifted and re-applied without leaving that evidence. Fibre tear or a destructible construction can be specified where the application wants additional physical damage as well. Surface or sub-surface numbering and barcodes available.
• P22H — leaves a security void message on the surface which can be rubbed off afterwards without permanent damage, so the packaging can be reused.
• P22G UV — clear permanent gloss with UV ink; both label and void message fluoresce under a blacklight.
• LLP — liner-less permanent labels. No backing liner to dispose of, and around 50% more label per roll, reducing waste, carriage and storage.
• Box TP — total transfer permanent tape for cartons, with surface or sub-surface numbering and barcodes.

Bag tape is specified by level, with each level adding an indicator:

• Level 2 — void at ambient temperature, plus cold void.
• Level 3 — adds a heat indication using thermochromic ink.
• Level 4 — adds security cuts, so the tape tears when interfered with.
• Level 5 — adds a hidden UV print for covert checking.
• Level 6 — adds water-activated ink, indicating moisture attack.

Choose the level from the attack methods that are credible in your operation, not from the highest number available.

Labels suit defined closure points, individual items and assets. Tape suits carton seams and volume sealing, by hand or on machine. Bags with integrated tape suit cash, evidence, duty free, samples and secure transfer where the container itself is the security.

Many applications use two together — tape along the seam and a numbered label for record-keeping.

Yes, more than anything else. Surface energy determines how well the adhesive wets out and bonds. High surface energy surfaces such as glass, metal and many coated boards bond readily; low surface energy plastics such as polypropylene and polyethylene, powder coatings and heavily recycled fibres are harder work.

Dust, oil, moisture, embossing and corrugation flute lines also reduce contact area. Where adhesion is marginal, the void may not trigger reliably — which is why we ask for the actual substrate rather than its description.

Yes. Application temperature affects whether the adhesive bonds at all, and service temperature affects whether the void behaves as intended. Chilled and frozen environments, and packs applied warm then chilled, need constructions specified for that range. Tell us both the application temperature and the coldest and warmest point in the journey.

• Custom print — logo, brand name, warnings, instructions or your own void message wording.
• Numbering and codes — sequential numbers, barcodes, QR codes and datamatrix, surface or sub-surface.
• Security features — UV inks, thermochromic inks, water-fugitive inks, security cuts, covert patterns.
• Format — custom sizes, roll widths and lengths, wound to suit hand or machine application.
• Material and colour — film or paper base, colour matched where the process allows.

Minimum quantities and lead times vary by construction. We will confirm both against the specification rather than quote a general figure.

Surface printing sits on the top layer of the material. It is versatile and cost-effective, and it can be abraded or altered.

Sub-surface printing is embedded within the construction, beneath the top layer. It resists abrasion, chemicals and alteration, which is why numbering and barcodes that need to survive the journey are usually specified sub-surface.

UV ink is invisible under normal light and fluoresces under a blacklight. It gives a covert check: if the label looks intact but the hidden message is missing or wrong under UV, the label is not the one that was originally applied. It is a verification aid for trained staff rather than a feature the general public will use.

A print that smears or disappears on contact with moisture. In bag tape it means an attempt to open and reseal the bag using water or steam leaves a visibly disturbed print, even where the tape itself is still in place.

A DR is a Design Reference. Everything we manufacture carries one, and it holds the key information about that specification — construction, print, size, wind direction, security features. Quoting your DR is the quickest way to reorder exactly what you had before.

A double numbering system: the label carries a number and a matching, removable numbered tab. The tab is peeled off and retained with the paperwork or scanned into your system, so the record and the sealed item share the same reference.

A deliberate weakening pattern cut into the label or tape so that any attempt to lift it cleanly causes it to tear along the cut lines, adding physical evidence alongside the void message.

An area intentionally left without adhesive, using stripe coating, so the label can be lifted from the liner easily by hand. It matters for speed and accuracy where labels are applied manually, and with gloves.

These describe how a label feeds off the roll. NEL (Narrow Edge Leading) feeds the narrowest edge first; WEL (Wide Edge Leading) feeds the widest edge first. Applicators and printers need a specific orientation, so confirming NEL or WEL avoids rolls that cannot run on your machine.

Tape wound onto itself with no separate release liner. There is no liner waste to dispose of, more tape fits on each roll, and it runs on standard hand and machine dispensers.

Cutting the label to a defined shape using a die — standard rectangles, radiused corners, bespoke shapes, and the security cut patterns described above.

Because the same construction can behave very differently on two packs. What needs to be known is the surface it goes onto, the temperature at application and in transit, how the pack is handled, who applies it and how quickly, and who is expected to check it later.

Get those five right and the product choice usually narrows to one or two options.

Test on your own packs, not on a flat sample panel. A workable sequence:

• Apply as your team would, at the real line speed and temperature.
• Leave for the dwell time the adhesive needs before testing removal.
• Attempt removal the way you expect interference: slow peel, blade, heat, cold, solvent, moisture.
• Photograph intact, interfered and evidence states, side by side.
• Repeat after a real or simulated journey, including the coldest and warmest points.

Keep the failures. They tell us more than the successes.

Cold chain covers temperature-controlled storage and transport for food, pharmaceuticals and chemicals. For tamper evidence it introduces three issues: application onto cold or condensating surfaces, adhesive performance held at low temperature, and void behaviour when a pack is warmed back up.

Constructions intended for ambient use should not be assumed to work at chilled or frozen temperatures — the void may not trigger as intended.

A structured review of how tamper evidence performs in your operation: where seals are applied, whether they suit the surfaces and temperatures, how they are checked, what is recorded, and where in the journey the gaps sit. The output is a specification and a checking process, not simply a product list.

Yes — tamper-evident labels and seals with void messages, unique numbering or covert features are widely used across pharmaceutical packaging, distribution and clinical supply, including vials, cartons, totes and controlled-drug transfers.

Regulatory requirements vary by market and product, and the responsibility for compliance sits with the product owner. We will specify a construction to your requirement and provide the technical data to support your own assessment.

Yes. Electronics packaging and warranty sealing, retail returns and anti-wardrobing, e-commerce parcels, food and beverage, aviation, cash in transit, laboratory samples, industrial and OEM parts are all served from the same core constructions, specified differently. Browse applications to see examples.

Ideally the pack itself. Failing that: what is being secured, the surface material, application temperature and method, the journey and its temperature range, the attack methods you are worried about, who checks the seal, and the volumes involved. A photograph of the pack sealed and a photograph of a failure are worth several paragraphs of description.