Cold foiling transfers a metallic or holographic layer onto printed adhesive without a heated die. A flexo or offset unit prints UV-curable adhesive, the foil web contacts it at a controlled nip, UV energy cures the bond, and the carrier is rewound while the decorative layer remains only in the printed image.
Because the image is defined by printed adhesive rather than by tooling, cold foiling behaves much more like a printing station than like a finishing operation. That single difference shapes everything else on this page: what equipment you need, which variables you have to control, and where the process is a poor fit. If you are looking for the underlying terminology first, our cold foil stamping definition covers it, and the step-by-step press guide goes deeper into operator-level sequence.
How does cold foiling work?
The process runs as a continuous chain rather than a set of discrete stages. Adhesive is imaged in the artwork shape, the foil web is brought into contact with the still-wet adhesive under controlled nip pressure, and UV energy cures the adhesive while the foil is held against it. The carrier film then separates and rewinds, and the metallised layer stays only where adhesive was printed.
Everything downstream depends on that adhesive image being clean and consistent. If the adhesive film is uneven, under-cured or contaminated, the release behaviour of the foil changes and the defect shows up as missing metal, ragged edges or foil where it was not wanted. Because curing is instantaneous, the decorated surface can normally be overprinted in the same pass, which is why tinted metallics and gradients over foil are practical on a cold foil line.
What equipment and materials does the process require?
Cold foiling is always inline with another printing process, so the starting point is a press that can carry a cold foil module: a sheetfed offset press with a foil tower, a narrow-web flexo press with a foil unit, a wide-web line for film substrates, or a hybrid digital line with a foil station. Most established press builders offer retrofittable modules, so a new press is not usually required.
On the consumables side you need three matched items: a UV-curable cold foil adhesive, a cold foil transfer web with a release system suited to that adhesive, and a substrate whose surface energy and absorbency support the bond. The adhesive delivery system — anilox volume in flexo, plate and blanket condition in offset — determines how much adhesive reaches the sheet, and the UV system determines whether that adhesive cures properly at production speed.
Which variables control transfer quality?
Transfer quality is rarely decided by one setting. In practice the recurring control points are:
- Substrate surface. Sealed, low-absorbency stocks hold a defined adhesive film. Uncoated or highly absorbent stocks pull adhesive into the sheet and dull the metallic effect unless primed.
- Adhesive film weight. Too little adhesive gives incomplete transfer; too much causes squeeze-out, edge halo and contamination of the release layer.
- Nip pressure. The foil has to contact the adhesive evenly across the web or sheet. Uneven nip loading is a common source of one-sided transfer faults.
- Web tension. Slack web creates wrinkles and creases; excessive tension distorts fine detail and can break the web at splices.
- UV cure energy. Under-cure leaves tack and poor adhesion, over-cure can embrittle the bond and affect overprint behaviour. Lamp output should be checked with a radiometer rather than assumed.
- Foil grade and release force. Release has to be tuned to the adhesive: a grade that runs cleanly with one adhesive can shed foil dust or leave voids with another.
Treat published figures for coat weight, tension and UV dose as starting points for a press trial, not as specifications. Press model, lamp system, substrate, coverage and foil grade all shift the working window. The cold foil press setup checklist sets out the order in which to verify these, and the cold foil defects photo guide helps translate a symptom on the sheet back to a cause on the press.
Where does cold foil perform well?
Cold foiling is strongest where the decoration is graphic rather than tactile, and where run length or substrate sensitivity makes a separate finishing pass unattractive. Typical fits include pressure-sensitive labels for wine, spirits and cosmetics, folding cartons with large or intricate metallic areas, and flexible films that would distort under a heated die.
It also performs well when the brief calls for coloured metallics. Because the foil surface can be overprinted inline, a single silver foil plus process or spot colours can produce rose gold, champagne, emerald and gradient effects without additional foil SKUs or a second pass.
What are the practical limitations?
The process is flat. There is no sculpted relief in the cold foil station itself, so briefs that depend on embossed or debossed metal need hot stamping, or a separate embossing operation. Rough or heavily absorbent uncoated boards are also difficult, because the adhesive image spreads or sinks before the foil reaches it.
Foil economy is a second constraint. The carrier runs continuously, so isolated small decorations spread across a sheet or web consume more foil than their printed area suggests; ganging artwork and planning foil lanes is how converters recover that cost. Finally, some food-contact and pharmaceutical applications restrict UV-curable chemistry, which means low-migration adhesive systems and additional qualification work.
A full comparison with heated-die decoration, including tooling and cost behaviour, is set out in hot vs cold foil stamping; the short version is that hot foil still wins on relief and on very coarse stocks, while cold foil wins on speed, overprintability and heat-sensitive substrates.
How should a converter qualify a foil grade?
Qualification is about reproducing your own production conditions, not about accepting a datasheet. Run the candidate grade with the adhesive and lamp configuration you actually use, on the substrates you actually buy, at the speed you intend to sell.
A workable sequence is to start with a short adhesion and appearance check at low speed, then step the press up to production speed while monitoring transfer edges and foil dust, then hold a longer run to see whether release behaviour drifts as the foil roll diameter changes. Finish with the downstream checks that matter for the job — overprint adhesion, varnish or lamination compatibility, tape pull, scuff and any migration or compliance testing your market requires. Record the settings that produced an acceptable result so the job can be repeated.
What information should a buyer provide for a press trial?
The faster a foil supplier can narrow the grade, the fewer trial passes you pay for. Useful information includes:
- Press make, model and cold foil module type
- Substrate name, weight, coating and supplier
- Adhesive system and anilox or coating unit specification
- UV system type (mercury or LED) and available output
- Artwork character: solids, fine lines, halftones, coverage percentage
- Overprint, varnish or lamination applied after foiling
- Run length, target speed and any compliance requirements
If you would rather evaluate finishes before committing to a trial, our cold foil sample kit lets you review physical swatches against your own artwork and substrate first.
Frequently asked questions
Does cold foiling work on plastic film? +
Yes. Because no heat is applied to the substrate, cold foiling is widely used on PE, PP, BOPP and PET films. Bond strength depends mainly on the adhesive system and on the surface treatment of the film, so corona or primer condition should be checked as part of the trial.
Can cold foil be overprinted? +
In most cases yes, and it is one of the main reasons converters choose the process. Curing happens inline, so downstream stations can print over the metallic layer to create tints and gradients. Ink and varnish compatibility still has to be confirmed for each combination.
How fine can cold foil detail be? +
Fine positive lines and small type are achievable on well-maintained presses, but the practical limit depends on plate or blanket condition, adhesive rheology and substrate smoothness rather than on the foil alone. Determine the limit on a trial with your own artwork.
Does cold foil need a primer? +
Usually only on uncoated or highly absorbent substrates, where the adhesive would otherwise sink into the sheet. On coated papers, coated board and treated films the UV adhesive itself normally provides the anchor layer.
How does cold foiling compare with hot stamping? +
Cold foiling avoids heated tooling and runs inline, which favours speed, heat-sensitive substrates and overprintable metallics. Hot stamping remains preferable where sculpted relief or very coarse uncoated stock is involved. See our hot vs cold foil comparison for the detail.