Since they are on silver and subject to tarnish, daguerreotypes were put behind glass and sealed with paper tape so air cannot tarnish the plate (there often is some tarnish around the edges of the picture). This was then put into a little hinged case, similar to a womans compact.

What are daguerreotype cases?

Case — Daguerreotype cases are made from a variety of materials. The most common cases are made of wood covered with tooled leather or embossed paper. In 1854, thermal plastic union cases, noted for elaborate designs, came into use. Daguerreotype — A plate of copper, lightly coated with silver.

Why is the Calotype important?

The calotype process produced a translucent original negative image from which multiple positives could be made by simple contact printing. This gave it an important advantage over the daguerreotype process, which produced an opaque original positive that could be duplicated only by copying it with a camera.