JF Ptak Science Books Quick Post
Antoine Francois Jean Claudet, (1797-1867), began experimenting with Daguerreotype in 1840, and soon became photographer in ordinary to the Queen, being among the very first to practice Daguerrian portraiture in London. . He was very innovative and successful, and contributed many inventions and improvements in the cause of early photography, and was one of the first to use the collodion process.
In an article published in the Philosophical Magazine in 18491 Claudet asks some still-fundamental questions about photography that he feels are still unanswered. Asking questions out loud (so to speak) doesn’t happen that often in scientific and tech publications like this, and when they do, it is worth taking a moment to notice them.
Claudet asks and answers the following important questions:
- “Although the Daguerreotype process has during the last ten years been investigated by a great number of philosophers, and brought to a considerable degree of perfection by a still greater number of practitioners, it may appear surprising that the principal phaenomena upon which this new art is founded, are still enveloped in a mysterious darkness.
- What is the action of light on the sensitive coating?
2. How does the mercurial vapour produce the Daguerreotype image?
3. Which are the particular rays of light that impart to the chemical surface the affinity for mercury?
4. What is the cause of the difference in achromatic lenses between the visual and photogenic foci? why do they constantly vary?
5. What are the means of measuring the photogenic rays, and of finding the true focus at which they produce the image?