Hot foil stamping

In hot foil stamping, also called "Prägefoliendruck" in Germany, a layer of ink is melted onto the substrate using an embossing die under heat and pressure. A wafer-thin plastic film serves as a transport medium for the ink layer, which explains the name. The ink layer can also be "only" colourful, but very often contains real metal. This is why this printing process is often associated with gold or silver or even called gold embossing or silver embossing. Hot foil stamping is also one of the main processes for applying hologram effects to printed products.

Besides paper, cardboard and paperboard, many plastics or self-adhesive foils can also be imprinted in this way. The heat of the embossing cliché additionally smoothes the surface, so the results usually show very good light reflection, even a mirror-like effect on homogeneous materials.

Hot foil stamping as a printing process is mainly used for the following areas:

• Real metallic effects on printed products, such as texts or designs in gold, silver, copper, bronze or multicoloured metal.
• Hologram effects, e.g. as protection against forgery on certificates, diplomas or vouchers.
• To apply texts and designs to materials that cannot be printed using conventional methods, such as bookbinding cloth or paper with a very structured surface.
• To transfer the positive attributions that exist for the precious metals gold and silver to advertised products, from a hotel brochure to business cards to the label of a champagne bottle.
• As a design element in graphic design, where the process's own appearance and the possibility of a deepening embossing create an attractive contrast to the surroundings.
• To enhance three-dimensional embossing by means of metallisation through light reflection

No! The name of the printing process unfortunately leads to the misconception that a film goes onto the paper. In fact, the foil is merely a means of transport. It contains the colour pigments and the real metal that are to be applied to the paper. Under heat and pressure, this layer of ink is then melted off the carrier foil and transferred to the pressed-on paper. The film has now done its job, is wound up and finally sent for recycling.

This depends on 3 factors: Surface to be imaged, type of embossing foil and print motif. Smooth, even and closed surfaces allow for more subtleties than rough or even coarsely structured surfaces. Metallised embossing foils allow greater fineness than thickly pigmented colour foils, which tend to smear and blur fine details. And, of course, the print motif must also be able to be reproduced on a tool.

In the ideal case of smooth, coated paper and metallic embossing foil, we recommend a minimum line thickness of 0.2mm and 0.4mm for negative recesses. Other surfaces and foils need more.

Before discussing tenths of a millimetre, however, 2 thoughts should come to the fore: When enlarged on the screen, a filigree design often looks great. In practice, however, it should also be reader-friendly for the people using it. With metallic embossing foils, such as gold or silver, more embossing surface also means more light reflection surface, i.e. "Design coarser = get more precious metal effect!"

For scatter motifs, the limit is the sheet format of the foil stamping machine minus a processing margin, for us around 680x980mm with a print sheet 720x1020mm. For full-surface motifs, approx. DIN A3 is a rough guide. BUT: As is well known, many roads lead to Rome! In the case of large-area metallisation in gold, silver or hologram effect "Rainbow" or "Laser" silver, it may be cheaper for us to metallise the entire sheet using a different process. We then simply overprint the metallisation on the areas of the image that should not be metallic.

Simply put: The country! J As the saying goes, "Austria and Germany are two countries separated by the same language!". The term "Prägefoliendruck" is used in Germany, while in Austria "Heißfolienprägung", or often even shorter just "Folienprägung", has become established.

Hot foil stamping is often used where other techniques have reached their limits or do not work at all:

First and foremost, hot foil stamping can be used to apply real metal to paper and card. In this way, the look of real gold, silver or copper can be achieved, and in a shiny and deceptively real way. Metallic inks are also available, but they are very discreet in comparison. For example, a "golden" offset ink often looks more like an ochre brown with a slight metallic shimmer, but never like real bright gold.

Metallic hologram effects, for example as forgery protection on certificates, diplomas or vouchers, are also usually applied via hot foil stamping.

And there are many materials that cannot be printed with conventional offset, such as bookbinding cloth for hardcover books, paper types with a very structured surface or dark-coloured cardboard. Special processes such as hot foil stamping or screen printing are needed here.

Hot foil stamping also offers many possibilities as a design element in graphic design, such as the metallic or holographic effects mentioned above. It is also possible to intentionally create a deepened, tactile impression in the material. Three-dimensional embossing can also be enhanced by light reflection through metallisation.

Graphic studios and advertising agencies working in an international corporate environment often use English in their documents and print data. The German "Prägefoliendruck" or Austrian "Heißfolienprägung" then usually becomes "hot foil", "hot stamping" or "hot foil stamping". In British English, the term "foil blocking" is also used. An equally common but erroneous or error-prone term is also "foil embossing", as "embossing" does not only mean embossing, but specifically raised embossing in combination with hot foil.

Hot foil stamping is the more versatile process in terms of colour tones, pattern designs and different embossing variants such as structure or relief. Above all, the number of possible substrates is immense: paper, cardboard, paperboard, wood, bookbinding cloth and much more. Moreover, not only smooth but also roughly structured surfaces can be imprinted. It is also the only printing process that offers the light embossing that many customers want as that certain something extra and often demand in greater depth.

Cold foil stamping is limited to smooth surfaces, such as coated paper, and also has a slightly reduced gloss level with gold and silver. Textured embossing is also not possible. There is absolutely no embossing for this. Very fine details can also be reproduced, up to and including grids. Metallised surfaces are often overprinted here as well. Cold foil stamping has its niches, for example, in the reproduction of facsimiles or in mixed techniques where partial metallisation is to run into each other with classic offset printing.

Technically speaking, cold foil stamping is not actually embossing. An adhesive is transferred to paper via a printing plate. The adhesive then plucks or tears the metal particles out of a passed metallised foil, whereupon they adhere to the paper.

Yes, in principle hot foil stamping or embossed foil printing is also possible on transparent paper. However, please note:

• The results that can be achieved depend very much on the type of tracing paper.
• In the case of rather flat motifs, there may sometimes be pinholes in the motif ("pinholes").
• From the reverse side of the paper you can also see through to the reverse side of the metallisation, this see-through is usually rather cloudy, inhomogeneous, greyish and matt, but not in the colour and homogeneity of the front view
• Most embossing foils are sufficiently opaque, e.g. for using the tracing paper as a dust jacket for a book. However, they are not light-blocking on the tracing paper when illuminated by transmitted light, if this is important for your project.

Alternatively, transparent rigid plastic films can also be imaged with hot foil stamping in many cases.

The most popular colours for hot foil stamping are hot foil stamping gold and hot foil stamping silver. These are available in both glossy and matt. Gold is available in many colour nuances, silver also in silver grey (smoked metal) or in the look of brushed aluminium.

In terms of colour, there are various hot-foil embossings in copper and bronze shades to match gold.

In addition, there are many metallic shades such as red, green, blue, turquoise, pink and many more.

Iridescent hologram effects in rainbow colours are most strongly available in silver, but occasionally also in gold or chromatic colours.

Non-metallic embossing foils, so-called pigment foils, are available in black, white and many bright colours.

The spectrum is rounded off by effect foils, such as mother-of-pearl colours, rainbow colour gradients, iridescent oil puddle optics, patterns with antique patina, watercolour optics, transparent foils or translucent, only partially opaque foils.

Glazing" is the process of pressing an image motif under pressure and high heat into a paper, cardboard or book cover material. The high temperature can cause an optical change in the surface at this point. A slightly shiny sheen can develop, the surface can appear smoother and more homogeneous or even the colour tone can become slightly darker. Some materials react very strongly, others little or hardly at all. A test therefore pays off. In addition, there are a number of book cover materials, such as those from Winter & Company, that are specifically listed as "thermoreactive". Here, the glazing effect is particularly impressive. A thermoreactive material with a textured surface has the strongest effect. Here, glazing adds a colour tint and also partially smoothes the structure out of the material.

Glazing is carried out on hot foil stamping presses, but without foil and with considerably more heat than foil stamping. For a good effect, therefore, it also requires a machine with strong heating power.