Niépce's early experiments had derived from his interest in lithography and centered around capturing the image in a camera (then called a camera obscura) to result in an engraving that could be printed somehow by lithography. The asphalt process or heliography required exposures that were so long that Arago said it was not fit for use. Nevertheless, without Niépce's experiments, it is unlikely that Daguerre would have been able to build on them to adapt and improve what turned out to be the daguerreotype process.