The first partially successful photograph of a camera image was made in approximately 1816 by Nicéphore Niépce,[6][7] using a very small camera of his own making and a piece of paper coated with silver chloride, which darkened where it was exposed to light. No means of removing the remaining unaffected silver chloride was known to Niépce, so the photograph was not permanent, eventually becoming entirely darkened by the overall exposure to light necessary for viewing it. In the mid-1820s, Niépce used a sliding wooden box camera made by Parisian opticians Charles and Vincent Chevalier to experiment with photography on surfaces thinly coated with Bitumen of Judea.[8] The bitumen slowly hardened in the brightest areas of the image. The unhardened bitumen was then dissolved away. One of those photographs has survived.