(R.D.Z.) Rudolf Ditmar / Rudolf Ditmar Erben
Vienna, and Znaim in Moravia, Austro-Hungarian Empire. Now called Znojmo, Czech Republic.
Kunstthonwaaren-Fabrik / Manufacture of art pottery wares
Karl Rudolf Ditmar: born 3rd May 1818, in Preslau in the state of Brandenburg, died 22nd March, 1895, Znaim, Moravia.
Rudolf and his brother Friedrich relocated to Vienna in 1839, where they traded in oil lamps. On the 5th August 1841, as the Ditmar Brothers, they opened their own metalwork facility manufacturing oil lamps. In the 1850's Rudolf developed the "Viennese Moderateur Lampe", an adjustable oil supply mechanism, which came to dominate world markets. Due to changes in fashion, lamp bodies changed to ceramic from metal due to the infinite number of design possibilities available. Therefore, in 1879, Rudolf open an art pottery factory in Znaim, originally manufacturing lamp bodies in earthenware, however some porcelain has also been seen. Around 1890 they also started producing a range of steins. Rudolf died in 1895. In 1910, the company now called Rudolf Ditmar Erben (heirs) was purchased by the K. u. K. priviligierte Wilhelmsburger Steingut- und Porzellanfabrik and merged with the Brothers Urbach of Teplitz-Turn, (now Teplice-Trnovony, Czech Republic). In 1913, the companies were purchased by Triptis A.G, (The same company that purchased Wicke-Werke in the 1920's). However the Ditmar factory again became independent, when the factory was confiscated by the newly founded state of Czechoslovakia in 1919 and operated as Ditmar-Urbach, under its previous owner, Richard Lichtenstern. In turn it was again confiscated by the Austrian Government, as part of the Anschluss in 1938, to become Ostmark-Ceramics A.G. and subsequently nationalised in 1945. In 1947 Richard's son Kurt, who had emigrated to the U.S. and changed his name to Conrad H. Lester, took back the company and changed its name to ÖSPAG (Österreichische Sanitär-, Keramik- und Porzellan-Industrie AG). This was eventually taken over in 1967 by the Keramik Holding Laufen, which is now part of the ROCA group. Gebrüder Horn has also ended up in this grouping.
Reference: Ditmar History Lichtenstern Porcelain Marks & More WT-Pempel
R. Ditmar, Vienna & Znaim, Paraffin / Kerosine lamp, post 1879. 
Ink stamp on the base of the R. Ditmar, Vienna & Znaim, Paraffin / Kerosine lamp. 
Ceramic pot or ornament stand, dated c.1890. It is moulded in three separate pieces and is approx. 32" or 82cms tall . 
Impressed base mark on pot or ornament stand above. 
Mould #20027, dated c.1892
Internal capacity mark on mould #20124, dated c.1892._edited-1.jpg)
Impressed maker's mark on mould #1955, dated c.1890's.
Ink stamp 1879 - 1910. R.D.Z.= Rudolf Ditmar Znaim Impressed stamp 1879 - 1910. R.D.Z. on wheel rim with impressed spokes on the interior. 
Ink stamp 1879 - 1910 after which time the factory was purchased by K. u. K. priviligierte Wilhelmsburger Steingut- und Porzellanfabrik. 
Example of capacity mark, painted inside the rim. _edited-1.jpg)
Mark from the base of a porcelain lamp. 
Mould number impressed #1584. Ink stamp 1879 - 1910. R.D.Z.= Rudolf Ditmar Znaim. 
Brass "Sonnenbrenner" Sun Burner lamp, probably dated between 1841 and 1879.The glass mantle and shade are missing. 
The turn knob for raising the wick on the above lamp. 
Mould #20124, dated c.1892 
Impressed maker's mark on mould #20124, dated c.1892. 
This mark was used from 1910 to 1913, after the takeover by Wilhelmsburger Steingut- ind Porzellanfabrik. 
This mark was used from the date of the creation of the country of Czechoslovakia in October 1918 to the Anschluss in March 1938. 