Steel engraving
also Siderography
Steel engraving is one of the traditional gravure processes. The steel engraving can be a high sharpness and fine detail of the items to be printed can be achieved. As an industrial printing process of steel engraving, is now used for the production of securities (such as banknotes, stamps) and generally used photopolymer or engraved metal printing plates. In the application of steel stitch for surface finishing an engraved steel die for the transfer of the subject is used. At the same time, a pilot head deforms the substrate. Therefore, the steel stitch is also counted among the embossing process.
Technical background
For the steel engraving two forms are required: the steel punch with depressions and the male body as a counter pressure with raised surfaces. Both forms are usually produced by hand by means of engraving. The ink is applied to the steel cylinders. With a doctor blade the excess ink is then removed. The color remains liable only in the wells. Subsequently, the substrate is pressed with the aid of the male mold at a very high pressure in the wells. So the color is almost completely transferred and the substrate is deformed simultaneously.
Effect
The designs are reproduced with high sharpness and detail refinement. The visual effect is also achieved haptic. By the deformation of the subject and from the rear is visible. The steel engraving can achieve high coverage. Therefore, it is possible to display bright objects on a dark background opaque. Depending on the use of color are matte or glossy effects realized. In Europe, people generally use the shine effect, based on the use of paint oil-based paints, which, after drying, high gloss. In the USA, however, there is enhanced matte surfaces to visually delineate the steel engraving from the thermal relief printing. Here are water-based paints are used. Even gold and silver ink can be transferred.
Application possiblities
The steel engraving method is ideal for the reproduction of the finest lines, hatches and smallest typographic elements. Line widths of 0.3 pt to 8.5 pt can be represented easily. The steel engraving, provides the opportunity to refine high-quality printing products due to this high level of detail and his unique and elegant appearance. The application of steel engraving ranges from representative letter amenities on business cards, folders, brochures and private papers to letters of recommendation and referrals. In addition, through the steel stapling with a large counterfeiting security. Therefore, it is used for a long time for the value papermaking. Furthermore finds the steel engraving process used in the production of certain certificates of authenticity. The steel engraving can be combined with offset and screen printing.
Limitations
In the preparation of the subject is paying attention to the vector or image data. The design should be applied as a spot color on its own layer and uniquely named. Image data may also contain grayscale and must be deposited as cross-line screen in the file. Large areas should be avoided as the print area is limited per printing pass. Fine lines on the other hand have no problems in the implementation. For the choice of printing considerations to its surface mass and direction are important. Should be noted that the formation of the subject on the materials back is greater, the thicker this. Longer lines of text should always be parallel to the direction of the printing, otherwise adjust unsightly undulations. Due to the high amount of ink transferred is schedule for the complete dehydration of the color will be a time of 24 hours. Only after further processing without abrasion and print damage is possible. Further processing of the steel engraving prints can inter alia occur in laser printers.
Costs
Steel engraving is one of the most expensive finishing options. Many steps are still performed by hand. The use of these exclusive refining variant therefore worthwhile only for large print runs.
Sources and additional literature
[1] Beckmann, Till; Morlok, Franziska: Extra: Enzyklopädie der experimentellen Druckveredelung; Birkhäuser Verlag, 2009
[2] Kipphan, Helmut: Handbuch der Printmedien – Technologien und Produktionsverfahren; Springer-Verlag Berlin Heidelberg, 2000, Seite 439
[3] Printperfection
[4] Conzelmann, Willi: Stahlstich-Prägedruck: Von Haptik mit Höhen und Tiefen, PublishingPraxis September/Oktober 2010. Seite 51