What was the benefit of a calotype over a daguerreotype open study?

Daguerreotype: developed in collaboration with Niepce; a single-image produced on a glass plate treated with silver iodide and chemically developed by exposing it to mercury vapour. A unique image, not reproducible. Daguerre names the invention after himself overlooking the collaboration of Niepce who had died six years earlier. In 1839 Daguerre receives a patent from the French government and a monthly stipend.