Keywords: Herschel study of oak leaf.gif en Study of an oak leaf by Sir John Herschel 1792-1871 26th February 1839 from his hypo fixing experiments Apart from the examples of lace this negative photogenic drawing is Herschel's only contact image of a real object rather than an engraving or other form of illustration The mark on the leaf seems to be a large J cs Studie listu dubu snímek zhotovený Herschelem 26 února 1839 při testování ustalovače - negativ http //www mhs ox ac uk/features/ephotos/ephoto21 htm photo John Herschel 1839 PD-old John Herschel |