the “Hyalotype”-process to produce a transparent black-and-white photographic image on glass to be projected with a magic lantern. The brothers presented their invention for the first time at the World Fair 1851 in Paris and drew great attention. Very soon the first commercial produced photographic slides (in black-and-white, sometimes hand coloured) came up in the market. However, at the beginning with small success only. Professional showman stayed with hand painted-slides (antique statues as an exception).
The photographic slides had long been undervalued in Germany for their use in education and teaching, countries like America were one step ahead. A rethinking process started with the easy for anybody to handle and light intense introduction of a new type of projector, the so called scioptikon, invented by L. J. Marcy and patented 1868 in America. The scioptikon was soon offered in Germany by dealers like Romain Talbot in Berlin or Eduard Liesegang in Düsseldorf. Thanks to the tireless persuasive efforts of visionary individuals an awaking took place among scholars. The scioptikon went in the last decade of the century increasingly popular within educational institutions when the suppliers expand their offer of photographic slides into tens of thousands of different motives. For all sort of topics slide-sets became available. Whether images of countries in the world or scientific themes. The dealers made it easy for everybody to project photographic slides, textbooks were printed with explanations for the slide-sets or they offered complete sets for hire. Loan companies established before and after the World War One, like August Fuhrmann, Deutsche Lichtbild-Gesellschaft, Berlin and others. Companies like Seemann in Leipzig, Benzinger in Stuttgart or Liesegang in Düsseldorf offerd tens of thousands different motive. The popularity of photographic slides for institutions outlasted the Second World War and they were still in use till the 1960th. Parallel to this trend the photographic slide was discovered by private photographers.