<P> It was not until around the year 1800 that Thomas Wedgwood made the first known attempt to capture the image in a camera obscura by means of a light - sensitive substance . He used paper or white leather treated with silver nitrate . Although he succeeded in capturing the shadows of objects placed on the surface in direct sunlight, and even made shadow - copies of paintings on glass, it was reported in 1802 that "(t) he images formed by means of a camera obscura have been found too faint to produce, in any moderate time, an effect upon the nitrate of silver ." The shadow images eventually darkened all over because "(n) o attempts that have been made to prevent the uncoloured part of the copy or profile from being acted upon by light have as yet been successful ." Wedgwood may have prematurely abandoned his experiments due to frail and failing health; he died aged 34 in 1805 . </P> <P> In 1816 Nicéphore Niépce, using paper coated with silver chloride, succeeded in photographing the images formed in a small camera, but the photographs were negatives, darkest where the camera image was lightest and vice versa, and they were not permanent in the sense of being reasonably light - fast; like earlier experimenters, Niépce could find no way to prevent the coating from darkening all over when it was exposed to light for viewing . Disenchanted with silver salts, he turned his attention to light - sensitive organic substances . </P> <P> The oldest surviving photograph of the image formed in a camera was created by Niépce in 1826 or 1827 . It was made on a polished sheet of pewter and the light - sensitive substance was a thin coating of bitumen, a naturally occurring petroleum tar, which was dissolved in lavender oil, applied to the surface of the pewter and allowed to dry before use . After a very long exposure in the camera (traditionally said to be eight hours, but now believed to be several days), the bitumen was sufficiently hardened in proportion to its exposure to light that the unhardened part could be removed with a solvent, leaving a positive image with the light areas represented by hardened bitumen and the dark areas by bare pewter . To see the image plainly, the plate had to be lit and viewed in such a way that the bare metal appeared dark and the bitumen relatively light . </P> <P> In partnership, Niépce in Chalon - sur - Saône and Louis Daguerre in Paris refined the bitumen process, substituting a more sensitive resin and a very different post-exposure treatment that yielded higher - quality and more easily viewed images . Exposure times in the camera, although substantially reduced, were still measured in hours . </P>

How long did it take to take a photo in the 1800s