Cold Foil Basics

What Is Cold Foiling?

Cold foiling is a fast and cost-effective on-press process for applying foil to a variety of substrates—sometimes referred to as foil printing. In the process, the cold foil is applied to an adhesive image using a standard printing plate. The foil is affixed to the printed adhesive, creating an image prior to the application of printing inks.  The foil that does not adhere to the adhesive remains on a thin polyester liner, and waste is directed to a rewind spool. Because the adhesive is applied on press like an ink, no stamping die is needed. Once printed, the surface of cold foil images is often varnished to provide a durable surface. Because it utilizes a printing plate, the registration between the applied foil and the printed inks and varnish is press perfect. Cold foils are available in silver and gold, in addition to stock and custom holographic patterns. Overprinting offers a limitless palette of color options.

Production Basics

Cold foils offer not only economy and speed, but flexibility across printing methods and substrate:

  • Cold foil can be applied via:
    • Flexography
    • Offset Printing
  • Cold foil works well with the following inks:
    • UV Inks
    • Conventional Inks
    • Hybrid Inks
  • Cold foil is compatible with many substrates:
    • PS Label
    • Coated Paper
    • Paperboard
    • Film
    • Heat-sensitive Material
    • Plastic
    • Shrink Film
    • Tube
  • Cold Foils can be applied:
    • Under Inks or Over Inks
    • Under Laminate Coatings
    • Under Varnish
Features / Benefits

Offering not only shelf-appeal, cold foils offer differentiation to printers, designers, and brand owners who are ready and able to capitalize on their versatility and efficiency.

Brand Benefits

  • Enhanced print means clear product differentiation for marketers and retailers
  • ‘Stand-out’ eye catching retail and POP solution
  • Strong value vs. cost ratio
  • Cost savings and faster speed to market—no metal dies, no post-press foil application, no outsourcing
  • Expanded sales and marketing opportunities—unlimited run lengths possible
  • Increased security possibilities—cold foil can enable readability of Electronic Article
  • Surveillance (EAS) tags can be customized with unique holographic images or patterns
  • Broader brand-enhancing possibilities: temperature-sensitive materials like in-mold labels or shrink labels can be decorated
  • Recyclable 

Design Benefits

  • Provides a reflective surface with on-press application
  • Available in a variety of silvers, golds, and custom or stock holographic patterns as well as transparent patterns
  • Infinite spectrum of color possibilities by overprinting silver or holographic patterns
  • Available for many design applications due to production efficiencies
  • Ability to retain textures, such as on linen effect substrates. (Although for predictable results, cold foil is typically recommended for smooth, coated surfaces)
  • Flexibility to produce large, solid areas as well as fine detail, halftones, small fonts, and knockouts
  • Cold foil is applied selectively, eliminating the need for opaque white
  • Professional differentiation with the ability to provide cost-efficient value-added print
  • Can be paired with UV Casting for further on-press enhancement possibilities
  • No deformation of the substrate (elimination of temperature/pressure influences compared to hot stamping)
  • No edge/image shadow marks on the rear of the print substrate - important, for example, on magazine covers 

Printer Benefits

  • Strong ROI as a value-add print enhancement
  • Key differentiator among competitors
  • Good overprintability, compatible with conventional, UV and hybrid inks
  • On-press application at normal press speeds
    • Up to 14,000 sheets per hour for offset printing
    • Up to 120m/min for flexography
  • Press-perfect registration control
  • Fast setup with no up-front tooling or dies
  • Requires no make-ready work / machine setting and make-ready times are eliminated. Setup times are therefore very low. Color and design changeovers can be achieved as quickly as with straight print projects.
  • Rapid job changeovers
  • Efficient for both short and long print runs
  • Minimal investment for new market entry
    • Existing presses can be retrofitted with cold foil modules
    • Possible to install in 2-3 days
    • No stamping dies required, only standard printing materials: plates, rollers, washing agents, and rubber blankets
    • Limited operator training necessary
  • Increased economies possible
    • “Foil save” features
    • Running multiple parallel foil rolls
    • Print-length indexing for foil feed
  • Ease of post-press processing (cold foiling does not deform the substrate)
  • Possible to foil temperature sensitive materials, such as in-mold labels or shrink labels
  • Run any combination of wide and narrow web presses
  • Easy label application: No tensioning of the paper occurs when transferring cold foils, even for large-area designs. This allows the labels to be subsequently applied more quickly.
  • Flexibility to design changes
  • Ease for job testing / press proofing
Limitations / Challenges
Cold foils have some limitations and can pose certain challenges which can be easily addressed.
  • Cold foils do not work well on absorbent substrates
  • Foil saving is possible; but only with special equipment features
  • Typically no inline embossing/debossing, these processes must happen post-press
  • Relative to hot foil, cold foil can offer a slightly lower brightness level, depending on the surface properties of the material, print quality of the adhesive and the varnish
  • Cold foiling requires complete cleanliness to minimize surface defects
  • Cold foils typically are not available in deep shades, due to limitations of thru-curing

For advice on specific challenges, we will soon be publishing Flexo or Offset technical content. Until then, please contact your local ITW Technical representative.

Alternatives to Cold Foil

Cold foil is not a replacement for traditional metallic enhancements, but rather an opportunity to expand the use of foil into broader markets and applications. Some markets which were previously inaccessible to foils, such as publishing, are benefitting from its versatility and efficiency. Cold foiling is a fast and flexible finishing technology, with a high level of flexibility in design, and suitable for any length of print run.  The following describes product characteristics and performance attributes which should help determine the best match for a given project. 

Cold Foil vs Hot Foil

While cold foil is transferred onto a surface as a flat application, hot foil stamping bonds to a surface using heat and pressure. This differentiation results in a few key implications.

  • Schedule and budget: Cold foiling is typically faster and less expensive than hot stamping. With no dies, tooling time and costs are eliminated. With on-press processing, application of cold foils can run at press speed. Hot foils can also be applied on press in rotary environments, although dies are still a requirement.
  • Coverage: If the foiled image is positioned only on a small area of a sheet, hot foil stamping may be most cost-effective. For moderate- to full-coverage, cold foils are generally ideal.
  • Stock: The cold foil process is not as effective on dry, porous or dark stocks. On these, the hot stamping process excels in performance, opacity, and brightness.
  • Combination stamping and embossing: Hot foils are often embossed concurrently with an application. The cold foil process is a flat application and cannot be embossed concurrently with the application. It can be embossed post-press.
  • Aesthetics: Significant strides have been made with respect to the shine or brilliance of cold foil and today it takes a critical eye to discern the true visual differences. Hot foils, however, do naturally impart a distinctively tactile stamped feel, due to heat and pressure in the application.
  • Layering: While some applications could employ either hot or cold foil, others can benefit from the sophisticated pairing of both finishes. This pairing can provide a striking contrast. For example, a tobacco pack may pair a flat silky cold foil with a luxurious embossed hot foil emblem. 

Cold Foil vs Metallized Substrates

Metallized substrates come ready to print. For high-impact metallic coverage, metallized substrates do offer exceptional brilliance. Deciding between the cold foils and metallized substrates will depend on several factors:

  • Run length and coverage: Metallized substrates can be purchased in sheet or web form but the additional expense substantially increases the final cost of the job. Still, for large runs with full metallic coverage, metallized substrates are often the most cost-effective choice. For short-to-medium runs and/or light-to-moderate coverage, cold foil may be preferable.
  • Whites: If whites, skin tones, light, or bright colors are critical to the design, they are easily achieved with cold foils by “knocking out” foil areas. With metallic substrates, an opaque white must be applied prior to print layer and will require additional print units.
  • Colors: An infinite range of colors can be achieved by overprinting either cold foils or metallized substrates.
  • Schedule: Lead-times to obtain metallized substrates are typically longer than those for cold foils.
  • Application: Certain end-use scenarios that require foil removal can only be achieved with cold foil or transfer-metallized substrates. For example, in blister pack security because foil removal is evidence of tampering. Lottery scratch tickets also utilize the foil removal properties of cold foil and transfer-metallized substrates.
Comparison Chart

 

Hot Foil

Cold Foil

Laminate

Transfer

UV Casting

Application: Offset

Off-line

In-line

Off-line

Off-line

In-line

Application: Flexo

In-line

In-line

Off-line

N/A

In-line

Print Speed: Offset

Full

Full

Full

Full

Full

Maximum Speed: Flexo

Medium

Full

Full

N/A

Full

Brightness

High

Medium

High

High

Low

Coverage

Spot

Any

Full

Full

Any

Accessories

Tooling

Adhesive

Opaque White

Opaque White

Varnish

Recyclable

Yes

Yes

Difficult

Yes

Yes

Supply Base

High

Medium

High

Low

Low

Initial Cost

High

None

None

None

None

Average Job Cost

Low

High

High

High

Low

Design Changes

Inflexible

Flexible

Flexible

Flexible

Flexible

Ideal Run

Long Runs (Flexo)
Short Runs (Platen)

Long and
Short Runs

Long runs

Long runs

Long and
Short Runs

Choosing the Right Foil

Cold foil performance characteristics will vary based on the manufacturer. While the basic components of cold foil are essentially the same, each manufacturer uses unique formulations and processes which result in variable properties.

Cold foils are often trialed to test properties such as release, printability, adhesion, and thru-cure.  In addition to foil properties, outcomes can also be influenced by making adjustments on press. 

Release refers to the transfer of foil from the carrier onto the substrate. Proper release is required to successfully provide a range from heavy to solid coverage as well as fine detail on a given job.

Printability is a fairly comparable property among foil brands. Most cold foils accept UV inks, hybrid inks, and conventional or water-based inks reliably. Certain applications have more stringent adhesion requirements and may require a trial.

Adhesion is the property measured by the adherence between foil and substrate. This is typically tested with tape as well as scratching and rubbing to determine how durable an image will be. Cold foils are designed with a tiecoat which allows the cold foil adhesive to adhere to the metallized aluminum layer.

Thru-cure refers to the process of curing the cold foil adhesive.  UV energy must be transmitted through the foil to initiate the curing of the cold foil adhesive.  Foil transparency and aluminum thickness are attributes which strike an important balance in quality cold foils. These properties are typically well-adjusted in top foil brands.  Foils with a thick aluminum layer and low transparency will often fail a tape test or not transfer at all.  Conversely, a highly transparent foil will not be bright and may have a grey hue. 

Explore ITW Foils' cold foil solutions here.

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