The calotype and daguerreotype are early photographic processes invented in Europe during the mid-19th century. William Henry Fox Talbot, a British inventor, is recognised for the calotype. Louis Daguerre, a French designer and chemist, is credited with the daguerreotype. The calotype process used paper coated with silver iodide to create a negative image, while the daguerreotype created a positive image on a light-sensitive, silver-coated plate exposed to mercury vapour. Photographs made by these processes are known as calotypes and daguerreotypes -- each with its advantages and disadvantages.
Advantages of the Calotype
Perhaps the most obvious advantage of the calotype process is that multiple copies of an image could be made. By printing the silver iodide paper negative onto silver chloride paper, the image was reproduced. Another favourable aspect is the calotype's method of printing on paper, which made for easier handling. At the time of its invention, the calotype was the simplest photographic process, making it more appealing to amateurs.
Disadvantages of the Calotype
A clear disadvantage of the calotype image is its inferior quality of detail. While simple to use and inexpensive, paper also contains flaws that mar the quality of calotype prints. Calotypes do not have the razor-sharp definition of daguerreotypes. Materials used in the original calotype process were not as light-sensitive as those of the daguerreotype, making the exposure time slower. Another drawback is that calotype prints, as paper images, are susceptible to fading and other conservation problems.
Advantages of the Daguerreotype
Among the distinct advantages of the daguerreotype is its superior quality of detail. This is because the picture plane is solid silver and there is no grain on the surface of the print. The image quality is much finer than paper -- or even film. The daguerreotype process was ideally suited to portraiture, which increased its popularity, far surpassing that of the calotype. Another favourable characteristic is that daguerreotypes, while delicate and fragile, can last forever if properly conserved.
Disadvantages of the Daguerreotype
A definite disadvantage of the daguerreotype process is that it was impossible to duplicate an image. The images produced are positives rather than negatives. While great for portrait sittings, the daguerreotype method could only capture subjects that were absolutely still, because the length of the process. It also proved a more complicated, expensive and labour-intensive medium that did not appeal to amateurs.