In 1861, the physicist James Clerk Maxwell announced his discovery of the three-colour process on which the technology of colour photography is still based. To mark the anniversary, New Scientist looks at the inventors, tinkerers and pioneers who made colour photography possible.
Fixing an image
The French inventor Joseph Nicéphore Niépce created the first permanent photographic image in 1822. He coated a sheet of glass with bitumen, which hardens in sunlight. After placing the sheet inside a camera obscura and exposing it for 8 hours, he washed away the soft, unexposed bitumen with lavender oil, leaving a permanent image. The picture here, The View from the Window at Le Gras, is the oldest surviving example of the technique and dates from 1826.
Pioneer or fraudster?
Exactly when the first colour photograph appeared is something of a mystery. In 1851, a US Baptist minister called Levi Hill announced that he had perfected a colour technique. However, he refused to share the details of his process until he had a patent. None was ever granted, but in 1856, he finally revealed his methods – by which time he had been dismissed as a fraud by his peers.
Researchers at the National Museum of American History in Washington DC and the Getty Conservation Institute in Los Angeles later showed that Hill's technique could reproduce colours crudely, but that he had also added pigments by hand.
(Image: Levi Hill/Information Technology and Society Division, National Museum of American History)
The theoretical foundation of colour photography was laid in 1861. In a lecture at the Royal Society in London, the physicist and mathematician James Clerk Maxwell showed that it was possible to recreate all the colours in nature by combining red, green and blue.
He demonstrated the idea by taking three black-and-white transparencies of a tartan ribbon through red, green and blue filters. He then superimposed these three images using three projectors – each with a filter of the respective colour.
The result was a full-colour image. The image above reproduces the effect, but was produced later. Maxwell's additive colour synthesis technique is the basis behind much of photography and printing today.
(Image: James Clerk Maxwell)
Instead of mixing primary colours to form an image, another way to make a colour image is to subtract colours from white light. This technique was pioneered by the French photographer Louis Ducos du Hauron in the late 1860s. He called it heliochromy.
(Image: Louis Ducos du Hauron)
Towards the full spectrum
In the early days of colour photography, most pictures rendered colours poorly. The silver halides used in light-sensitive emulsions were highly sensitive to blue light but not to other colours.
The German photochemist and photographer Hermann Wilhelm Vogel solved this problem in 1873 when he discovered that certain dyes could improve the sensitivity of silver halides to red and green.
Vogel’s ideas were initially applied to black-and-white film but paved the way for true colour photography in the 20th century.
Colour for the masses
In the late 19th century, colour photography was a pursuit that only a skilled – and wealthy – chemist could hope to master. But in 1895, a US inventor called Frederic Ives created a cheaper and easier way of making and viewing such photographs. The so-called Kromskop system generated three black-and-white transparencies taken through filters, as Maxwell had done. But Ives also made a viewer that combined the light from these images to create an image that was not only in colour but 3D too. It was popular for a while but the impracticality of making three exposures for each image eventually led to its demise.
This stereoscopic image is the earliest known colour photograph of San Francisco, taken in the aftermath of the 1906 earthquake.
(Image: Smithsonian Institution)
Commercial colour images
In 1907 the Lumière brothers launched the Autochrome plate, an additive colour-based system that became the first commercially successfully form of colour photography. In the next 30 years, their company sold millions of plates that could reproduce colours vividly.
(Image: Helen Messinger Murdoch)
The emergence of modern film
The problem with Autochrome was its steep price and the long exposure time it required. So when Eastman Kodak launched a cheaper, more sensitive competitor called Kodachrome in 1935, it was immediately successful. Kodak produced Kodachrome until 2009, when it was phased out because of falling demand due to the widespread adoption of digital photography.
This photo shows the view along Shaftesbury Avenue from Piccadilly Circus, London, in 1949.
(Image: Chalmers Butterfield)