Foil blocking (hot foil stamping)

Blocking foil is a thin film built in layers: a carrier, a release layer, the colour or metallised layer, and a heat-activated adhesive. A metal die is made from your artwork, heated in the press and brought down onto the foil and the board together. Where the die touches, the adhesive bonds and the foil releases; everywhere else the foil lifts away with the carrier.

Foil is a separate process from printing. It is applied after printing and lamination and before the box is cut and creased, or to the wrap before a rigid box is covered. Each foil colour needs its own pass and its own die. Foil is registered to the print, but there is a small tolerance between the two, so artwork should not rely on foil sitting exactly against a printed edge.

The foil choices are wide. Metallic foils include gold, silver, copper and rose gold, in bright or brushed finishes. Pigment foils give flat, opaque colour, including white and black, and can put white onto kraft or dark papers where ink cannot. Holographic and pearlescent foils add movement, and clear gloss foil gives a subtle shine.

Foil combines well with other finishes. Foil and emboss together, using a sculpted combination die, gives a raised metallic logo in one pass. A foil deboss presses the logo into the surface with a crisp metallic floor. Foil on matt or soft-touch lamination creates strong contrast, although soft-touch needs a foil made to bond with its coating.

Cold foil is a different process, applied in line on the printing press with an adhesive and often overprinted with colour. It suits larger areas and metallic effects mixed with print, and is typically used on longer runs. Most custom packaging uses hot foil blocking, which gives the crisp, slightly pressed finish people associate with premium boxes.