Guilloche
The guilloche is a fine ornamental pattern made up of several interwoven and overlapping lines. The lines form cord-like, often asymmetrical , closed diamonds , ellipses or circular paths.
The engraving of guilloches on metal is used as guilloching designated. For this purpose, guilloche machines or guilloches, a form of lathes specialized for this purpose, have been used since the 17th century . In German there are also the expressions Rund- und Geradzugmaschine (Zug = Guilloche); in English, the terms are rose engine and straight line engine.
In the printing technique , the guilloches were used for decoration and gray gradation. Since in earlier times the raster technique, which is widespread today, was not common to color graphics with graduated color tones (gray scale), line patterns were used. The denser the network of lines, the darker the printed area appeared.
history
Depending on the source, the invention of the guilloche is explained differently:
- The inventor is said to be the Frenchman Guillot.
- The term “guilloche” comes from the French word for “ graver ”, an engraving tool .
- Hans Schwanhardt († 1621) is said to have invented it and his son-in-law Jacob Heppner († 1645) contributed to its spread.
- Jakob Degen invented a guilloche engraving device between 1816 and 1820.
Pattern printing
In earlier times, guilloches were mainly used as a security feature when printing banknotes , securities , passports and identity papers in order to make counterfeiting more difficult, as the guilloches on the printing plates that were still engraved at the time could not be easily reproduced 1: 1. At the same time, they make manipulation by mechanical shaving of original documents more difficult, since such interventions are evident through the interrupted guilloche pattern. Due to more modern anti-counterfeiting measures that can now be incorporated into such documents ( OVI , OVD , micro- fonts , etc.), guilloches are no longer used as often.
Jewelry production
Less complex line patterns are used in watches and jewelry than in the production of print templates for certificates and banknotes. In contrast to printed guilloche patterns, the spatial design of the pattern in the material is also taken into account here.
Guilloches on cans, mugs, pocket watch lids and ballpoint pens have been popular in recent times; they stand out very clearly on silver thimbles .
Guilloche is a dying craft. It was done in piece work and is no longer profitable today . Objects and videos can be seen in the jewelry workshop of the German Museum of Technology in Berlin , including works of art by the guilloché master Walter Zaiß , who died in 2001 and who helped set up the exhibition.
The goldsmith school in Pforzheim is currently still training on guilloche machines and guilloche machines are on display in the Technical Museum in Pforzheim .
In the watchmaking industry in Germany and Switzerland , there are still a few companies that have mastered the guilloché technique of watchwork parts or dials.
Prominent guillocheurs
Carl Peter Fabergé and Abraham Louis Breguet are known for their guilloche jewelry and watches .
Others
- Numerous companies and institutions, including the Federal Financial Supervisory Authority (BaFin), use guilloches as logos .
- Gideon Fairman is described in a paper by Horace H. Furness as the inventor of engine turning (= guilloche).
See also
- Forgery of ID
- Epicycloids
- Counterfeit money
- Security feature
- Security features of banknotes
- Spirograph (toy)
- Forgery of documents
- Cycloid
literature
- Eugen von Philippovich: Curiosities / Antiques . Klinkhardt & Biermann, Braunschweig 1966
Web links
- Math Games - Guilloché Patterns
- Answer to the question: "What kind of a machine did Faberge 'use to engrave the gold under the enamel on his famous eggs and other irregular shapes?"
- Blog explains guilloché patterns in watchmaking
- Kit of a round pull machine from the USA
- Program for creating guilloches ( Mac OS X )
- www.guard-soft.com/cerberus.html - Windows-based program for creating guilloches
- Article that describes how to use the Grapher utility (Mac OS X) to create guilloches
Individual evidence
- ↑ Guilloche in the eLexikon (excerpt: Meyers Konversations-Lexikon , 1888; collective of authors, Verlag des Bibliographisches Institut, Leipzig and Vienna, fourth edition, 1885–1892; 7th volume: Brain - Hainichen, page 913)
- ↑ Picture of a guilloche machine
