An exquisite late-nineteenth century French daguerreotype (photo on glass) from Patricia's kitchen at Chanteduc. She exclaims "I love this photograph! The family looks so Provençal, to imagine them, living in a chateau - they're all dressed up! Who does that anymore? This has been hanging in the little window in my kitchen for 35 years - so I love these people! There's even a dog!"

The daguerreotype, developed by Louis Daguerre (French) in 1839, was the first publicly announced photographic process. Originally, daguerreotypes were produced on a silvered copper plate, but experimentation led to the use of glass as a medium as well.

The shift to glass for daguerreotypes was primarily for two reasons. First, glass provided a supremely smooth and stable base, allowing for a more refined and detailed image that was not always achievable with the textured surface of a metal plate. Second, the transparency of glass introduced new possibilities for viewing and displaying photographs.

To create a daguerreotype on glass, the process involved several steps:

1. Cleaning: The glass was meticulously cleaned to ensure no particles interfered with the image's clarity.

2. Sensitization: The glass was treated with iodine vapors, creating a light-sensitive surface of silver iodide.

3. Exposure: The prepared plate was exposed in a camera. This exposure to light developed the image directly on the glass.

4. Development: The latent image on the glass was developed using mercury vapor, which amalgamated with the exposed silver iodide, creating a visible image.

5. Fixing: The image was made permanent by removing the remaining light-sensitive silver iodide with a solution of sodium thiosulfate.

Using glass allowed for sharper and more stable images, which made daguerreotypes on glass a valuable innovation in the evolving history of photography, particularly for finer applications such as portraiture and scientific imaging.