In science, one person’s discovery can open the door to a rush of advancements, supplemental developments and ancillary activities. Such was the case when word came out of France about the discoveries of Louis Daguerre and the fledgling science of photography.
In his article Into the Light: John William Draper and the Earliest American Photographic Portraits, historian Howard R. McManus writes of the many people in the early nineteenth century who were experimenting with light and chemistry in an effort to capture photographic images, and how they were galvanised when details of French artist Daguerre’s processes were made public. Among them were such luminaries as Samuel Morse, Henry Fox Talbot, and John William Draper.
Draper, born in Lancashire, England, on May 5, 1811, has been credited with producing the first clear photograph of a female face, in about 1839, and the first detailed photograph of the moon, in 1840.
Draper’s work in photography was an outgrowth of his research in photochemistry, and McManus writes that he “made portrait photography possible by his improvements on Daguerre’s process”, which was the first practical method of making permanent images with a camera. The daguerreotype process produced direct positive images on a silver-coated copper plate.
McManus says Draper was among the first practitioners of photography to immediately use his scientific knowledge of the important difference between the visual and chemical focus. He understood that light rays towards the violet end of the spectrum had the most intense photographic effect. This allowed him to speed up the process and build more effective lenses.
He immigrated to the US in 1832 and wrote several books on a range of topics, including the successful 1874 work History of the Conflict between Religion and Science, in which he proposed the theory of intrinsic hostility in the relationship between the two fields.
As a chemist, Draper in 1841 came up with what is known as the Grotthuss–Draper law (also called the principle of photochemical activation), which states that only light that is absorbed by a system can bring about a photochemical change.
In 1843 Draper constructed a “tithonometer”, a device for measuring the intensity of light, based on an earlier discovery that light causes hydrogen and chlorine to combine progressively.
In 1847 he proved that all solid substances become incandescent at the same temperature, that thereafter with rising temperature they emit rays with increasing sensitivities to refraction, a quality known as refrangibility, and (a fundamental proposition of astrophysics) that incandescent solids produce a continuous spectrum.
For his researches on radiant energy, Draper received the Rumford Medal of the American Academy of Arts and Sciences in 1875. He died on January 4, 1882.