Many Zsolnay ceramics are noted for the use of the eosin process that was introduced in 1893. The name refers to the Greek goddess of dawn Eos. The secret Eosin technique which Vilmos Zsolnay developed creates iridescent metallic colors that are unique to every piece and unrepeatable. Eosin glaze renders porcelain in colors including shades of green, red, blue, and purple that change with the angle of reflection.
The Zsolnay factory was established by Miklós Zsolnay (1800–1880) in Pécs, Hungary, to produce stoneware and other ceramics in 1853. In 1863, his son, Vilmos Zsolnay (1828–1900) joined the company and became its manager and director after several years. He led the factory to worldwide recognition by demonstrating its innovative products at world fairs and international exhibitions, including the 1873 World Fair in Vienna, then at the 1878 World Fair in Paris, where Zsolnay received a Grand Prix. In 1893, Zsolnay introduced porcelain pieces made of eosin. Frost-resisting Zsolnay building decorations were used in numerous buildings specifically during the Art Nouveau movement. By 1914, Zsolnay was the largest company in Austro-Hungary.