Portrait of a daguerreotypist displaying daguerreotypes and its cases. Photographer/Unknown. Image source: Wikimedia Commons
Making a daguerreotype was an arduous process. At first, the plates would be kept wrapped in paper, but the images would rub off. So instead, they had to be framed in glass covers. To prevent tarnishing, the air inside the covers would have to be replaced by an inert gas. Then, the daguerreotype would be mounted in a protective housing.