Early Experiments with Lithography
The term "heliography" was coined by Joseph Nicéphore Niépce to identify the process by which he obtained his earliest photographic images.
Niépce began experimenting with lithographic printmaking—which led to his invention of heliography—because of his inability to draft images by hand. During his trials with lithography, he experimented with light-sensitive varnishes and then with images produced in camera, but he was unable to prevent the images from fading. Niépce discovered that he produced his best results while using a solution of bitumen of Judea, which dated back to the ancient Egyptians but continued to be used for making lithographic engravings in the 1800s.
In 1822, Niépce successfully made a heliograph from an engraving of Pope Pius VII, which was destroyed during an attempt to copy it some years later. Over the next few years, Niépce experimented with bitumen on pewter or zinc plates that could be inked for printing. His best results came in 1826 with the copying of an engraving of the Cardinal Georges d'Amboise in which Niépce invented the first successful form of photomechanical reproduction.
The First Photograph
Finally, in 1826 or 1827 the chemical process, the power of the camera, the successful quest for permanence, and the combined curiosity and clarity of the inventor Joseph Nicéphore Niépce all came together. He coated a pewter plate with the same solution from his previous experiments and placed the plate into a camera that was looking out from an upstairs window of his house at Le Gras. After an exposure of at least eight hours, the plate was washed with a mixture of oil of lavender and white petroleum, dissolving away the parts of the bitumen that had not been hardened by light. The result was the permanent direct positive picture you see here, a one-of-a-kind photograph on pewter. It renders a view of the outbuildings, courtyard, trees, and landscape as seen from that upstairs window.