Identifying Loetz Glass

In 1879, Susanne transferred the company to Maximilian von Spaun, the son of her daughter Karoline. One year later, von Spaun hired Eduard Prochaska and the two of them modernized the factory and introduced new, patented techniques and processes, transforming the glassworks into one of the foremost art glass manufacturers during the Art Nouveau period at the turn of the twentieth century. Loetz Glass throughout its history has been characterized by a number of historical periods that have shaped the style and build of the their products.


Exciting innovations in Historicism glass, included Intarsia and Octopus glass and the very popular marbled ‘marmorisierte a glass which imitated semi-precious stones like red chalcedony, onyx and malachite. Success at exhibitions in Brussels, Munich, and Vienna were crowned by awards at the Paris World’s Exposition in 1889.


The glassworks created large numbers of its own new designs of iridescent, trailing Art Nouveau glass, sometimes in collaboration with wellknown artists and designers like Marie Kirschner and Franz Hofstötter (aka Franz Hofstätter). The zenith of Loetz Art Nouveau glass was epitomized by the Phänomen series of designs, much of it designed by Hofstötter, which won a Grand Prix alongside the likes of Tiffany, Gallé, Daum and Lobmeyr at the Paris World’s Exposition in 1900.


Although 1904 saw yet another award, a Grand Prix at the St. Louis World’s Fair, sales started to lose momentum as interest   Phänomen glass waned. New artistic impulses were needed to compensate for a lack of in-house innovation, and Loetz Witwe intensified its collaboration with Viennese designers like Leopold Bauer, Otto Prutscher and Josef Hoffmann before, in 1909, appointing Adolf Beckert – a specialist for etched decoration – as its new artistic director. In the same year, von Spaun transferred management of the glassworks to his son, Maximilian Robert. Robert was less effective in managing the glassworks than his father had been, and financial problens worsened culminating in Loetz Witwe declaring bankruptcy in 1911. Injections of von Spaun family money and the continuing efforts of Prochaska meant that the glassworks could still operate, noticeably with etched designs byHoffmann, Hans Bolek and Carl Witzmann, but the company was dealt another blow when Beckert left in 1913. The new etched designs, plus newly introduced Tango glass were shown at the Deutsche Werkbund exhibtion in 1914.


The key concerns for collectors when it comes to collecting authentic Loetz Glass depends on colour, craftsmanship, signage, condition, form and décor.


Coloured glass is produced by introducing chemical impurities such as iron and copper oxide into the glass making process. Different metals and metal oxides produce different colours and, while copper and iron oxide remain fairly stable during the glass making process, creating green coloured glass, more exotic oxides (which duly create more exotic colours) can become unstable when exposed to very high heats. Green glass for example was the most commonly made and is therefore least covetable, while pieces made from unusual or multiple colours are a great deal rarer and more valuable.


Folded, fluted, flared, pinched, ruffled, trimmed or threaded rims, as well as evidence of a finely filed “pontil mark”, or dimple, are signs that the

piece has gone through more labour intensive processes. However, plain-rimmed pieces bearing pontil marks generally achieve the highest sums at auction.


Being able to successfully identify an authentic marking or signage is crucial prerequisite to glass collectors. In the case of Loetz Glass however,

it was a known fact that a major part of the Loetz production was not signed, which as a result had collector’s mistake a large proportion of Bohemian glass to be attributed to Loetz. The well-known label “Unsigned Loetz” was then applied to virtually any iridized piece of Bohemian origin.

It is commonly believed that only the pieces for export were signed. But according to Dr. Jan Mergl, co-author of “Das Böhmische Glas” and “H. Ricke, Lötz 1880-1940” there aren’t any general rules. He states that the pieces for the important exhibitions such as Paris, St. Louis and Milan, or those donated or sold to museums would often bear the Loetz signature, but again that was not a general practice.

It’s not unusual to find false Loetz signatures, but mostly they are easily distinguishable from authentic signatures. The engraved signature is always found on the polished pontil, and never on an unpolished area, nor on the side of a piece. The best known signature is Loetz Austria in engraved script. The authenticity of a Loetz mark can be immediately determined by examin-ing the characteristics of the engraving under high magnification. The engraving tool used by Loetz had a very high vertical oscillation.


Pieces of Loetz without a pontil mark will normally have a ground and polished rim, which ought to have a smooth, highly polished factory finish. However, if the piece does have a pontil mark, the rim should be fire finished. A piece of Loetz glassware bearing a pontil mark with a polished rim is usually the result of damage having been filed down and collectors should therefore be wary of investing in such examples.


Loetz is world famous for its diversity. Yet, they are known for maintaining an extremely standard of quality across all of their ranges. Loetz’s heyday coincided with the Art Noveau period, so pieces exhibiting Art Noveau characteristics and detailing are the most sought after. Many popular forms were re-produced with rim variation. As a general rule, purer plain rims achieve more at auction than ruffled rims.


Loetz decoration is thought to be complex, innovative, and among admirers of Loetz glassware, often sublime. For example, the experimental Phänomen decorative style is the most highly prized among Loetz collectors, the last Phanomen example to come to market, for example, sold to a collector in Germany for almost $30,000. There are numerous variations of this style, however attribution to a particular artist also positively impacts upon price.


The price of Loetz glass varies according to colour, craftsmanship, condition, form, décor and whether or not the piece can be attributed to a particular artist. For example, a rare Loetz Perl glass vase designed by Otto Prutsche sold in 2005, at Sothebys in Amsterdam for $59,000. While an unattributed, iridescent Art Noveau Cytisus vase, dating back to 1902 sold in Munich at Quittenbaum auctioneers for $28,000. Common, green Loetz ware can be found for

anything between $25 and $500, although rarer models have been known to fetch significantly more, while slightly more exotically coloured or decorated examples might achieve up to and above $5,000 at auction.