Guilloché

Guilloché is an engraving technique in which a very precise intricate repetitive patterns or design is mechanically etched into an underlying material with very fine detail. Specifically, it involves a technique of engine turning, called guilloché in French after the French engineer “Guillot”, who invented a machine “that could scratch fine patterns and designs on metallic surfaces”.Fact|date=March 2008 The machine improved upon the more time-consuming practice of making similar designs by hand, allowing for greater delicacy, precision, and closeness of the line, as well as greater speed.

Another account gives the credit of inventing this method to one Hans Schwanhardt (- 1621) and the spreading of it, to his son-in-law Jacob Heppner (1645).Fact|date=March 2008

Yet another account is that it derives from the French word for an engraving tool, not the engine turning machine.Fact|date=March 2008

Guilloche, usually spelled without the acute accent ("accent aigu") on the final e (and more often anglicized in English pronunciation as 'gi-'lOsh'), describes a repetitive architectural pattern widely used in classical Greece and Rome, consisting of two ribbons that wind around a series of regular central points. These central points are often blank, but may contain a figure, such as a rose. Guilloche is a back-formation from "guilloché", so called because the architectural motif resembles the designs produced by Guilloche techniques.

History

Engine turning machines were first used in the 1500–1600’s on soft materials like ivory and wood and in the 1700’s it was adopted for metal such as gold and silver. [ [http://users.lmi.net/~drewid/PWR_engine_turning.html What kind of a machine did Faberge' use to engrave the gold under the enamel on his famous eggs and other irregular shapes?] by Peter Rowe.] [ [http://www.professionaljeweler.com/archives/articles/2001/mar01/0301v.html Guilloché Enameled Luxuries: Engraved memories of a fanciful era] , Professional Jeweler Archive, March 2001.]

The last machines were manufactured around 1948–1949. [ [http://www.rgmwatches.com/engine.html RGM Watch Company: Engine turning Guilloche] ]

In the 1920s and '30s, automobile parts such as valve covers, which are right on top of the engine, were also engine-turned. Similarly, dashboards or the instrument panel of the same were often engine-turned. Customizers also would decorate their vehicles with by engine-turning panels similarly.

In modern English, the word "guilloche" is used to describe a narrow instance of guilloche: a design, frequently architectural, using two curved bands that interlace in a pattern around a central space. Some dictionaries give only this definition of "guilloche", although others include the broader meaning associated with guilloché as a second meaning. Note that in the original sense, even a straight line can be guilloché, and persons using the French spelling and pronunciation generally intend the broader, original meaning. ["The Century Dictionary: An Encyclopedic Lexicon of the English Language" By William Dwight Whitney 1889 ] [" [http://books.google.com/books?id=TtxYEMcL8H8C&pg=PA249&dq=Guillot+guilloch%C3%A9&num=100#PPA249,M1 Roman Pavements] " by Henry Colley March 1906 ] [" [http://books.google.com/books?id=FhIAAAAAYAAJ&pg=PA180&lpg=PA180&dq=guillot+guilloch%C3%A9&source=web&ots=lc7A8ldZy2&sig=2zJpjbh1o4L7bwjJsUKvYCF29cQ#PPA180,M1 The Anglo-Saxon Review] " By Lady Randolph Spencer Churchill 1901.]

The term Enamel - Guilloché , meaning simply "guilloché", is a back-formation that many be considered incorrect by some scholars. Although Enamel and Guilloché is a very popular and a strong enhancing pairing-first applied by Peter Carl Fabergé on the Faberge eggs in the 1880’s-they are nevertheless two separate techniques and were not applied to one another until Fabergé. [ [http://reviews.ebay.com/The-Guilloche-Enamelling-Process-and-Charm-Collecting_W0QQugidZ10000000001032914 eBay Guides - The Guilloché Enamelling Process and Charm Collecting ] ]

In today’s terminology

In consequence of the nature of the design, which is - usually - a series of lines that are, or look very much like they are interwoven into one another, any design engraved on metal, printed, or otherwise erected on surfaces such as wood, or stone, that go in a similar style of constant wriggling that interlock - or look like they are interlocking - with one another is referred to as guilloché.

Some of the more common ones are the following:

* Engraved (in metal, mainly sterling): in expensive timepieces (mainly pocket watches), expensive pens, jewelry charms, snuffboxes, hair-styling accessories, wine goblets etc. Examples of famous works of Guilloché are the engravings on Faberge eggs and on the nose of the Spirit of St. Louis.

* Erected: on stone for architecture, in wood for styling, on furniture or molding, etc.

* Printed: on bank notes, currency or certificates, etc., to protect against forged copies. The pattern used in this instance is called a spirograph in mathematics, that is, a hypotrochoid generated by a fixed point on a circle rolling inside a fixed circle. It has parametric equations. These patterns bear a strong resemblance to the designs produced on the Spirograph, a children's toy.
* In tiling: as a mosaic work such as those produced by the Cosmati family.

Other names for Guilloché

The engine turning machine characteristic of Guilloché is called by other names in specific uses:
* Rose engine (metalwork)
* straight line engine turning Tour à guilloché (metalwork)
* Holtzapffel lathe, named after the founder of an ornamental lathe manufacturer John Jacob Holtzapffel
* Decoration lathe (metalwork)
* Geometric lathe (security printing)
* Cycloidal engines (security printing)
* Ornamental turning or ornamental lathe (woodcarving).

The different types of the machines refer to different models and different times during the development of the engine-turning machine.

See also

* Roulette curve
* Fretwork
* Cloisonné

References

External links

* [http://ornamentalturning.net/craft/ Ornamental Turning & Engine Turning]
* [http://demonstrations.wolfram.com/GuillochePatterns/ Guilloché Patterns by Michael Schreiber] The Wolfram Demonstrations Project
* [http://www.pledge.co.uk/pledge_and_aldworth/ref/refconts.htm The Illustrated Engine Turning Reference by David Pledge]
*
* [http://www.maa.org/editorial/mathgames/mathgames_02_09_04.html Guilloché Patterns by Ed Pegg, Jr., Math Games, MAA Online, February 9, 2004.]
* [http://www.filahome-stamps.com/stamps/stamps_g.htm Stamp Collecting Encyclopaedia: Letter G Definition of Guilloche]
* [http://www.europastar.com/europastar/watch_tech/nicolet9.jsp What does the expression “guilloché” mean? Professor J. C. Nicolet Answers.]