Browsing by Author "Lierke, Rosemarie"
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- ItemEarly history of lampwork - Some facts, findings and theories Part 2. Fire or flame? Lampworking techniques in antiquity(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1992) Lierke, RosemarieNumerous early glass artifacts show typical features of lampwork. However, with the exception of few examples, it is impossible that true lampworking has been employed. The manufacturing method of these artifacts can only be explained by a related technique: open-fire working of glass. Α surprising result of this study is that the open-fire working of glass seems to have been used generally as glass manufacturing method up to the time of glass blowing. Tiny multicolored-decorated beads are evidence of lampwork in the Early Iron Age. Several examples of blown vessels from Roman times show that a single pointed hot flame had been used during the manufacturing process at the furnace.
- ItemGlass bowls made on the potter's wheel A new approach to ancient glass technology(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1991) Lierke, RosemarieEarly glass vessels were made by winding a glass thread onto a core which was fixed to a metal rod. This core-forming technique could not be used for the manufacturing of bowls, but a related procedure seems to have been employed. The investigation of spirally wound reticella bowls (3rd century BC to first half 1st century AD) has shown that they probably were made by spinning a reticella thread onto a mold on a potter's wheel. This manufacturing technique was experimentally reproduced. It is a fast and easy method, permitting a continuous production. No finishing by grinding or polishing is required. It is possible that certain other types of glass bowls, today claimed to be "cast and lathe cut" or "molded", have actually also been made on the potter's wheel. This is especially true for the so-called ribbed bowls.
- ItemIt was the turning wheel, and not the lathe Mold pressing and mold turning of hot glass in ancient glass vessel production(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1993) Lierke, RosemarieAfter a rehabilitation of the mold pressing method, the logical development from core forming and mold pressing to working glass hot on a turning wheel is shown. A manufacturing method known from ceramics - mold turning of the body and free turning of the rim - seems to have been used in glass first. Glass working by turning is mentioned in Pliny's description of ancient glass manufacturing methods. Up to now this has been incorrectly interpreted as cutting on a lathe. But vessels presumedly cut on a lathe show unequivocal signs of being made by turning hot glass.
- ItemOne more time - the making of the diatreta cups(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1995) Lierke, RosemarieIt is usually assumed that the Roman cage or diatreta cups are cut from a thick-walled blank. This theory is not in accordance with typical features of the ancient originals. It will be shown that the diatreta cups were cut from a double shell blank which was made hot on a turning wheel. The diatreta cups are evidence for a revival of the turning wheel production of glass in Late Roman time.
- ItemRecent investigations of early Roman cameo glass : Part 1 . Cameo manufacturing technique and rotary scratches of ancient glass vessels(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1997) Lierke, Rosemarie; Lindig, Matthias R.The manufacturing traces of ancient cameo glass were investigated. These investigations had a surprising result: early Roman cameo glass vessels have not been cut from overlay blanks. Instead, their manufacture appears to be related to the molding of multi-layered cameo glass gems and to the contemporary relief ceramics. The basic principle of the assumed cameo glass manufacturing process has been experimentally verified. Independently, the typical rotary "Scratches" of ancient glass vessels were investigated. Rotary Scratches are also a typical feature of early Roman cameo glass. The investigation confirms that these Scratches are not grinding marks. They were obviously generated during the hot manufacturing process.
- ItemThe 'grinding marks' of ancient glass - a critical assessment(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2002) Lierke, RosemarieThe theoretical reconstruction of ancient manufacturing methods depends on a correct interpretation of the extant manufacturing traces. An error with serious consequences was the misinterpretation of the typical scratches of ancient glass as grinding marks. Generations of archaeologists were convinced that especially the Roman glassworkers had a superior command of the art of glass cutting and grinding, which supposedly was never again surpassed in history. A few years ago, a new interpretation of the typical scratches of ancient glass was given, explaining the scratches as traces of the hot manufacturing process. Recent scientific investigations support this new perception. A summarizing presentation of the topic is given here to provide a realistic starting point for further research about the ancient glass manufacturing methods.