9 September 1839: Sir John Herschel takes the first glass-plate photograph
On this day in 1839, Sir John Herschel created the first glass-plate negative – a photographic technique that would remain in use in astronomy until the 1990s.
Cameras' have been around for a very long time. We know the Chinese were playing around with pinhole cameras in the fifth century BC. A pinhole camera is simply a box with a small hole in the front. Light enters through the hole and an upside-down image is displayed on the inside back wall of the box.
We also know the Chinese were aware that certain chemicals underwent a change when exposed to light. Combine the two and you should have a photograph'. Sadly, no ancient selfies have come down to us. But you never know
After that, the ancient Greeks toyed with the technology, then the Arabs and the Europeans after them, and on into the Renaissance. But it wasn't until the early 19th century that photography, as we understand it, was born.
Frenchman Louis Daguerre is famous for inventing the daguerreotype an early form of photography that used metal plates in 1839. But on 9 September of that same year, our own Sir John Herschel created a photographic negative on a glass plate, using silver chloride. It is he who introduced the word photography' into the English language.
Herschel was one of the great Victorian polymaths, happy to turn his hand at almost anything. Besides his pioneering work in photography, he excelled at botany, maths, chemistry and the family hobby: astronomy. His father was Sir William Herschel for whom the space observatory, which blasted off in 2009, is named.
But why talk about astronomy? Because the glass-plate method (with a few modifications along the way) was ideal for photographing the skies. So successful in fact, that astronomers continued to use it into the 1990s.
If all that wasn't enough for one man (besides naming a whole bunch of planetary moons), Herschel also invented the Cyanotype' method. Cyan is the blue colour used in printing, and the process was used to make blueprints'.