Relief printing [embossing]

The relief printing process is a family of printing methods where a printing block, plate, or matrix that has had ink applied to its surface, but not to any recessed areas, is brought into contact with the paper. The relief is the positive image and represents the printing surface. The areas of the printing plate with ink will leave ink on the paper, whereas the recessed areas of the printing plate will leave the paper ink-free.

The reliefs can be divided into: embossed and recessed. We speak of embossing technique when compared to the plane we obtain a rise; in the case of the hollow, however, compared to the plane we have a breakthrough of the material.

The reliefs are divided into three categories:

  1. flat reliefs. It is possible to choose between different types of interpretation of the character that, depending on the required processing, give a different result;
  2. multilevel reliefs. It is important to determine which part of the artwork should be in the foreground, which in the background, etc. etc.;
  3. the so-called artistic reliefs (or sculptured, in English), where the free interpretation of the artist (and of the management software programmed by him) will give an innumerable series of levels that will form the desired image. It is possible to obtain a 3D result to be examined on screen before proceeding to the realization of the plate.

The countersinks (taps to be placed on the pressure plate) are made of special resins and help speed up start-ups. Metallized or plasticized materials can withstand a considerable increase in pressure because the upper layer of film prevents breakage especially at the edges in the case of standard reliefs, multilevel and embossing.

On the other hand, in the case of artistic reliefs, the metallized or plasticized materials do not allow to “accentuate” considerably the various details of the cliché that the artist has interpreted. Machines that have a heated surface can certainly help with the temperature for the deformation of the printing support (50° is normally the ideal temperature for this operation even if it is plasticized material).

Relief of any kind is greatly enhanced by artwork. Sometimes, even if the relief is perfectly executed on white paper, during the production phase it could be not very evident visually and the quality would be determined only by touch. However, there are no rules to make this kind of evaluation without testing.

Artistic embossing can be done simultaneously with both standard or multi-level embossing and hot stamping. With modern engraving technologies, the relief can be perfectly controlled in its shape and excavation, whether it is simple, multilevel or artistic sculpted. The latter, precisely because of its difficulty of reproduction by possible counterfeiters, guarantees a high level of security even on an industrial scale. In the case of the artistic plate for dry relief, it is in fact possible (starting from the master engraving) to produce as many duplicates as the large format printing requires. For this reason we can speak of an artistic result on an industrial scale.

Simultaneous hot stamping and embossing

This process, which combines hot stamping and embossing in a single step, is accomplished with a sculpted, multi-layered engraving (usually brass), with the edges of the image area sharpened to allow for foil cutting’. As you can imagine, great care must be taken during the design phase when choosing paper colors, textures, weights and inks. The register then proves critical to the success or otherwise of the work. The thickness of the substrate can also limit the operator, depending on the press used: for example, very thin papers can cause some problems on large format machines. Similarly, the choice of particular papers affects the visual effect of the foil: 25% or 100% cotton papers, parchment, laid paper and other porous papers dampen the glossy effect of some foils.

Although technologies have helped modernize the process, hot foil and embossing is still an art, where experience is a deciding factor in a product’s success. An experienced printer can guide the choice of job type with certainty of results for both hot stamping and embossing.

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