Process of embossing
Embossing is one of the key techniques used to refine printing. It consists in physical deformation of the ground so that raised elements are formed on it. This technique uses dies in which the concave pattern is engraved. In contrast to letterpress, where the embossed material lies on a hard flat surface, the convex embossing uses a pressure element in the form of a flexible material, e.g. rubber, or a counter-matrix (counter-die). Counter-die is like a negative matrix. It has the same pattern, only inverted and raised. After embossing, an impression is obtained on the material, which is convex on one side and concave on the other. Embossing can highlight the logo, ornament, text, graphic sign or any shape. The best relief effects give shapes as simple as possible. The accented spatial element is clearly perceptible to the touch and is more visible. Embossed elements are, for example, credit cards with embossed numbers, medicine packaging with embossed Braile text, business cards, but also cosmetics packaging, price tags, clothing items, loyalty cards, etc.
Types of pressings
Three-dimensional (3D). This type of embossing requires very accurate pattern preparation and accurate matrix preparation. The three-dimensional embossing is similar to a bas-relief. Applies properly only to 3D graphic elements. For example, ordinary embossed inscriptions do not make sense in the 3D technique. Nowadays 3D embossing dies are made only by 3d engraving.
Pseudo 3D. The 3D embossing effect can be achieved using chemically etched dies. Due to the physicochemical properties, the matrix immersed in the chemical solution will be etched deeper in places where the elements are larger, and shallower in places where the elements are small. By using chemical etching and proper design preparation, we can get the impression of a three-dimensional pattern.
Single level (2.5 D). The most commonly used embossing, where all elements are pressed to the same height.
Blindprint - blind stamping
Finishing can occur on both printed and unpainted spots. One of the varieties of both embossing and letterpress is a blindprint, i.e. "Blind printing". It consists of stamping inscriptions or graphics in places where there is no printout. The embossing in this technique does not have to be done as accurately as in the case of traditional embossing, because it does not have to coincide with the bend.
Embossing vs. letterpress
Embossing finds wider application because it can be made on many materials: paper, plastics and leather. These materials can even be very thin. In turn, to get the right effect with letterpress we need to use thick material, so that the depression is deep enough to be seen or felt. In the case of more difficult materials, such as plastics or leather, pressing is carried out with a heated die, thanks to which the material retains its deformation. This is not important for paper.
Notes on the stamping technique:
Concavity on the back. If the embossing is performed on only one layer of paper, the concave (recess) is visible on the reverse. The visible concavity effect is avoided when later laminating, i.e. gluing two or more layers of paper.