The first permanent photograph ever taken required at least eight hours of exposure time.

Joseph Nicéphore Niépce created the image 'View from the Window at Le Gras' in France. He used a process called heliography, which means sun writing. He coated a pewter plate with a type of asphalt called Bitumen of Judea. This material hardens when it is hit by light.Niépce placed the plate inside a camera obscura and pointed it out his window. The bright areas of the scene hardened the asphalt on the plate. The dark areas stayed soft. After eight hours, he washed the plate with lavender oil and petroleum. This removed the soft parts and left a permanent picture made of hardened chemicals.The long exposure time created a strange visual effect. Since the sun moved during the eight hours, shadows appear on both the left and right sides of the buildings. This original plate is now kept at the University of Texas at Austin. It is stored in a special case without oxygen to keep it from fading.Later, in 1839, Louis Daguerre improved this method. He used silver-plated copper and iodine vapor to make images. This new process shortened the wait time from eight hours to less than 30 minutes. These early experiments showed that light could cause physical changes in chemicals to record a moment in time.