Glass grinding

Cutting glass with rich decoration is a traditional handicraft technique of decorative glass refinement. Cut glass is used to decorate vases, bowls, flat trays, decanters, bottles, baskets, table drinking glass and other shapes of practical use.

From a technical point of view, it is the mechanical removal of glass with a free or bound abrasive. The cuts are made by means of discs (most often diamond, but also carborundum and water-cooled electrite) rotating around a vertical axis on a ball machine or around a horizontal axis on a trowel machine. The basic cuts are wedge, round, straight and square. Wedge cuts produce patterns in the form of stars, mules, goats, claws, Viennese mats or triangular, hexagonal or octagonal stones. The rounded cuts, for a change, give rise to the so-called cones, cones or spots. The purpose of the technique of cutting glass with rich decoration is to try to create a rich pattern from these elements, often spread over the entire outer surface of the product. The surface of the glass thus decorated reflects the incident light from the individual edges and thus creates a shimmering ornament.

Glass has been decorated in this way since the 17th century. The noble lustre of Czech cut glass is closely related to the invention of lead crystal, which is easy to melt and has excellent optical properties. At the same time, it is softer and easier to cut than soda-lime glass and the brilliance of the cuts is usually achieved by polishing in acid. Previously, lead crystal was melted and cut with 30% PbO, today most often with 24% lead oxide.

Originally, this glass was used to imitate precious stones in Venice. In our country it began to be melted after 1710. First in Turnov, later in Jablonec and Železnobrod.

The patterns that are cut today are based on the deep technical and artistic tradition of our region. The grinder, who is demanded the highest quality of workmanship, must not only be precise in the technique of the grinding itself, but it is also necessary for him to have a decorative imagination and a sense of composition to be able to tastefully combine individual elements, shiny and matt surfaces of the cut.   

Cutting glass with rich decoration is a highly valuable work of the human hand, enriched by artistic flair and the ability to improvise and create new decors.

Miroslav Valenta, former engraver at Sklo Šafránek  

Glass engraving

The technique of decorating glass by engraving is one of the very old, now traditional handicraft methods of decorative refinement of glass objects.

Its history and technical principle dates back to antiquity, when a similar method was used to create engravings of cameos and gems in natural, very hard materials - agates, later rock crystal. The technical and artistic peak of glass engraving came at the beginning of the 17th century, when the technique became more classical and remained so throughout the following periods of Baroque, Rococo and Classicism.

Glass engraving, or more precisely glass cutting, developed in the Czech lands during the reign of Emperor Rudolf II, a great lover of art. At that time, natural materials were increasingly replaced by fused glass, which facilitated the development of decorative techniques in the increased demand for table and representational glass. Cut glass thus contributed directly to the worldwide fame of Czech crystal and is still a truly royal craft today. 

Glass engraving (cutting) is a work specific for its handicraft, i.e. the transfer of human emotion and skill into an image on glass. It is a technique that is unmistakable and unfeasible with modern technology. 

What is its charm? It is practically cutting into the surface of a glass object. From the sampling of the glass and the individual cuts, the resulting image is composed and "modelled". Like a painter's brush, a sculptor's chisel or a printmaker's chisel, the engraver's tools are rotating wheels, most commonly copper, carborundum, electrite and diamond wheels. As the engraver works, he applies a thin layer of emulsion of emery powder and kerosene, pure kerosene or water to their circumference, forming a cutting wheel that can remove the hard mass of the glass and leave the necessary matte mark on it. By alternating different sizes and profiles of wheels, large areas of glass can be removed as well as miniature scenes composed of many details. An engraving is essentially a classical relief, but most often a negative relief (positive relief is used to a much lesser extent), which is sunk into the surface of the glass. The engraving only acquires vividness and plasticity when light passes through the object from behind.

Glass engraving is the most demanding glass refining technique. The quality of the workmanship directly depends on the time and precision that the engraver devotes to his work.

Miroslav Valenta, former engraver at Sklo Šafránek