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Some historic projectors just like the magic lantern can be regarded as predecessors of the overhead projector. The steganographic mirror probably came closest to how the overhead projector was used. German Jesuit scholar Athanasius Kircher's 1645 guide Ars Magna Lucis et Umbrae included a description of his invention, the "Steganographic Mirror": a primitive projection system with a focusing lens and text or footage painted on a concave mirror reflecting sunlight, mostly supposed for long-distance communication. In 1654 Belgian Jesuit mathematician André Tacquet used Kircher's method to indicate the journey from China to Belgium of Italian Jesuit missionary Martino Martini. The "solar microscope" was employed in early photographic experiments with photosensitive silver nitrate by Thomas Wedgwood and Humphry Davy in making the primary, but impermanent, enlargements of minute objects. Subsequently, in 1857 Baltimore painter David Acheson Woodward' patented a photo voltaic enlarging digicam, a big instrument operated out-of-doors. It used sunlight and copying lenses for enlargements from a small unfavorable onto massive photographically sensitized paper or canvas.
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