At the beginning of the 20th century, Johann Irlbacher learns the craft of glass polishing in a glass grinding shop in the Upper Palatinate. After the First World War, the gradual decline of the artisan flat glass production, which had been based in the Bavarian-Bohemian border region for centuries, begins – industrial processes produce flat and uniformly thin glass; the process of polishing becomes increasingly obsolete. To escape this structural change, Johann Irlbacher founds a glass processing company in a small workshop in Dietersdorf near Schönsee in 1935 and soon specializes in the production of photo plates and slide glass.