The invention of photography differs from important inventions in other fields in that, before the early years of the 19th century, there was no perceived need for such a process. The invention, when it occurred, owed as much to the perception by Niepce of an opportunity to automate the drawing stage in the production of lithographic prints, which had become popular in France, and the interest of Daguerre in the diorama, as to technological advances. The popular demand for prints appears to have followed the social changes that led to, and flowed from, the American Declaration of Independence and the French Revolution, and Tom Paine's Rights of Man .