I feel convinced that no more important discoveries have been made since Gutenberg's invention of the printing press and that our nature printing technique will herald a new era in the publication and pictorial representation of artistic scientific objects.
Alois Auer, Die Entdeckung des Naturselbstdruckes, 1853
Nature printing is a simple printing process that nevertheless allows for very accurate illustrations of botanical and zoological objects. Leonardo da Vinci was one of the first to experiment with impressions of plant leaves. The plant must first be dried and pressed before it can be used as an image carrier. Then it is set on a smooth base that is coated with printing ink. All raised parts of the plant are thereby coated with colour and can be used to make a direct impression. This process produces a highly detailed print of the specific plant specimen that is of equal scientific value as a real herbarium plant. The natural colours can be reproduced by means of additional colouring-in by hand.
The doctor Johannes Hieronymus Kniphof (1704-1763) first recognized the business potential of the plant prints and published the work Botanica in originali, das ist Lebendig Kräuter-Buch in 1733. A number of Kräuter-Bücher ("herb books") were subsequently published containing illustrations of this kind. The German Museum of Books and Writing owns the Ectypa vegetabilium by Christian Gottlieb Ludwig, published between 1760 and 1764 in Leipzig by Breitkopf and printed by Trampe in Halle. In the 19th century, the technique of nature printing was extended by means of impressing onto lithographic stones or lead plates. Alois Auer Ritter von Welsbach (1813-1869) perfected the latter method by double electro-plating the lead plates and thereby creating an intaglio plate. The accuracy that was possible with these prints could not be equalled by usual block printing using photographs until well into the 20th century. Nevertheless, this printing technique did not find widespread use because of its inefficiency.