Foils

Foils can come in many different varieties including metallic, pearlescent, holographic and transparent. These can be applied to paper using various methods including hot foil stamping and cold foil blocking.

Things to consider

• Use a 100% spot colour tint for foiled elements.
• Foiled elements must be hard edged and should not contain any gradients or feathering.
• All foiled elements should be set to overprint.
• Very fine details cannot be maintained. The minimum recommended stroke weight for fine details is 1pt. Anything below this may break up or fill in.
• Foil registration is far less accurate than ink, so there are more design considerations to take into account. This makes foil one of the more complicated special finishes in terms of set-up.
• Knocking out or aligning areas of opaque foil with printed elements can cause registration issues but this can be remedied. One method is to spread the ink under the foil which is known as trapping and the other is to use white ink to mask the foil for CMYK to then print on top.
• Foil can be set to overprint ink and vice versa (see the Printing on top of foil section below). Your Producer, Pre-Production Producer and the Printer should always be made aware of this printing order as it may not be apparent from your files.
• The CMYK printed over foil can look quite weak as the foil colour will show through. A method to reduce this colour alteration is to print white ink on top of the foil and then print the CMYK on top of that.
• It is recommended to protect foil from scuffing by either laminating or varnishing over the top of it. Matt lamination reduces the shine of the foil and Spot UV retains it.

Solutions to opaque foil registration issues

Duplication

Stroke alignment

Knock out text

Printing on top of foil

Ink can also be printed over foil substrates (pre-foiled paper) and areas of foil blocking. Printers have to use special UV cured inks to prevent drying issues since foil will not absorb ink in the way that paper does.

Additional things to consider

• Overprinting ink onto foil can be more expensive than overprinting foil onto ink.

• Ink is affected by the colour of the foil beneath it. The colour change cannot be simulated on screen so a wet proof is recommended.

• Spot white inks can be used to mask off areas of foil.

• Spot white ink over foil does not appear as bright as white paper.

• Spot white inks can be tinted, feathered and graduated, so they can essentially be used to create soft edged, foil masks.

• Printing over partially foiled designs presents registration issues on press, as ink cannot register (align) perfectly to a foiled edge. Inks can maintain better registration than foil.This is why it is recommended to use a spot white ink to mask off the areas in which the foil is not wanted. Then the CMYK and any additional inks only need to register (align) with the spot white ink and not the foil.

• It is often quicker and easier to set up the foil layer above the CMYK layer in your InDesign file. As long as the foil elements are set to overprint then the separations in your InDesign file and PDF will look the same. Just remember to inform Pre Production, Production and the printer that the ink are to be printed on top of the foil, as it may not be obvious from your file.

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