This was an improvement over the calotype process, discovered by Henry Fox Talbot, which relied on paper negatives, and the daguerreotype, which produced a one-of-a-kind positive image and could not be replicated.
Acest lucru reprezintă o îmbunătățire față de procesul de calotype, inventat de Henry Fox Talbot, care s-a bazat pe negative de hârtie, și față de dagherotip, care producea imagini pozitive unice, ce nu puteau fi reproduse.