Niépce's aim originally had been to find a method to reproduce prints and drawings for lithography. He had started out experimenting with light-sensitive materials and had made a contact print from a drawing and then went on to successfully make the first photomechanical record of an image in a camera obscura – the world's first photograph. Niépce's method was to coat a pewter plate with bitumen of Judea (asphalt) and the action of the light differentially hardened the bitumen. The plate was washed with a mixture of oil of lavender and turpentine leaving a relief image. Later, Daguerre's and Niépce's improvement to the heliograph process, the physautotype, reduced the exposure to eight hours.