A short history of photography

Before photography: the camera obscura

Long before film or sensors, people knew that light passing through a small hole into a dark room forms an upside-down image of the scene outside. Chinese writings from around the 4th century BC describe the effect, and the scholar Ibn al-Haytham studied it carefully around the year 1000.

By the Renaissance the camera obscura (Latin for “dark room”) had shrunk into portable boxes with a lens and a mirror. Artists traced the projected image to get perspective right.

The optics were ready; what was missing was a way to make the image stay. That needed chemistry.

The first fixed images: Niépce and Daguerre

Joseph Nicéphore Niépce coated a pewter plate with a light-sensitive asphalt called bitumen of Judea and left it in a camera for many hours, possibly days. The result, View from the Window at Le Gras, made in 1827 (often dated c. 1826/27), is the oldest surviving photograph taken with a camera.

Niépce worked with Louis Daguerre, who continued after Niépce died in 1833. Daguerre's process used a silver-plated copper sheet made sensitive with iodine and developed with mercury vapour. Exposures dropped to minutes.

The daguerreotype was presented publicly in Paris on 19 August 1839, and the French government released it free to the world. Each plate was a unique, mirror-like image with astonishing detail, but it could not be copied.

Negatives and glass: Talbot, collodion and dry plates

In England, William Henry Fox Talbot took a different route. His calotype, patented in 1841, produced a paper negative from which any number of positive prints could be made. That negative–positive idea became the backbone of photography until the digital era.

In 1851 Frederick Scott Archer introduced the wet collodion process: glass plates coated, exposed and developed while still wet. It was sharper than paper and faster than earlier methods, but photographers had to carry a darkroom with them.

Gelatin dry plates, proposed by Richard Leach Maddox in 1871 and made commercially later that decade, could be prepared in a factory and stored. Exposures fell to a fraction of a second, and handheld cameras became practical.

Film for everyone: Kodak, roll film and 35 mm

In 1888 George Eastman launched the Kodak camera with the slogan “You press the button, we do the rest.” It came loaded with enough roll film for 100 pictures; you mailed the whole camera back for developing and reloading.

Flexible celluloid roll film followed soon after and also made cinema possible. The 1900 Kodak Brownie sold for one dollar and put photography in the hands of children.

Oskar Barnack at Leitz built a small camera around 35 mm cinema film, and the Leica went on sale in 1925. Its 24 × 36 mm frame is the format we still call “full frame”.

Colour and instant pictures

The Lumière brothers' Autochrome plates, sold from 1907, used tiny dyed potato-starch grains as colour filters. The results were soft and dreamlike and needed long exposures.

Kodachrome, introduced by Kodak in 1935, was a colour slide film with fine grain and very stable colours. It was made until 2009 and became the look of mid-century colour photography.

Edwin Land's Polaroid camera arrived in 1948 and delivered a finished print within about a minute. Colour Polaroid film followed in 1963.

The digital turn

In 1975 Steven Sasson, an engineer at Kodak, built a prototype digital camera. It recorded a 0.01-megapixel black-and-white image onto cassette tape, and each picture took about 23 seconds to save (approximate figure).

Kodak's Bryce Bayer patented a colour filter pattern in 1976: a grid of red, green and blue filters, with twice as many green squares because our eyes are most sensitive to green. Nearly every camera sensor still uses this Bayer pattern and fills in the missing colours by interpolation.

Professional digital SLRs appeared in the early 1990s, and models such as the Nikon D1 (1999) and the Canon EOS 300D (2003) made them affordable. By the 2000s digital had overtaken film for most uses.

Phones and computational photography

Camera phones appeared in Japan in 1999–2000. Their tiny sensors could not match larger cameras, so manufacturers turned to software.

Modern phones take a burst of frames for every press and merge them to reduce noise and widen dynamic range. They estimate depth to blur backgrounds, combine several lenses and use night modes that stack many seconds of exposures.

This is computational photography: the final image is calculated as much as it is captured. The basic ideas, though, are still the ones on this site: light, aperture, shutter speed and sensitivity.