In the middle of the 19th century, however, popular portrayals of ghosts became a year-round staple, in part because photographers discovered that they could depict them.
The first ghost photographs were accidents. Early cameras required 30 seconds or more to take a photo. If someone wandered briefly into the shot, the resulting picture would contain their ghostly trace superimposed over substantial furniture, buildings or people who had held still for the full exposure.
