16 May 2011 Last updated at 12:23 ET

Article written by Phil Coomes Picture editor

• More from Phil

Pioneering colour photography

 

It's just a picture of a tartan ribbon and may seem unremarkable, yet it marks a crucial moment in the development of colour photography and forms the basis of the photographs we take today.

The photograph was first seen at King's College London during a Royal Institution lecture on colour theory by the Scottish physicist James Clerk Maxwell on the 17 May 1861 and the college is marking the 150th anniversary of that demonstration with an evening of talks celebrating his scientific discoveries.

The first permanent colour photograph was taken by Thomas Sutton who was working with Clerk Maxwell and is a composite of three black and white pictures, each one taken through a red, green or blue filter. The resulting slides were then projected through three similarly filtered lenses resulting in a colour photograph.

Looking at the ease with which we now capture colour pictures and transmit them around the world in seconds it's easy to forget that it was not that long ago news agencies were transmitting their wire photographs as colour separations, usually cyan, magenta and yellow - a process that relied on Clerk Maxwell's discovery. Indeed even the latest digital camera relies on the separation method to capture light.

As late as the 1980s wire photographs would be transmitted by news agencies such as the Associated Press and printed out by the client as three black and white pictures; these would then be photographed through the same filters and re-constituted as a colour print.

As electronic delivery took over this method moved to the computer, but even then the pictures would arrive in three parts ready for the client to reassemble. It was sometime before full colour transmission was widespread.

Having searched the basement archive here at Television Centre for a suitable example, the only one I have located so far where the separations and a colour hard copy exist is a picture taken during the assassination attempt on US President Ronald Reagan in 1981 that was issued by the White House at that time.

Reagan was injured as were three others, Secret Service agent Jerry Parr, White House press secretary James Brady and police officer Thomas Delahanty.

You can see the three flimsy black and white wire photos as small images above, though they are somewhat faded now. The small holes at the top of the prints were made for registration purposes when re-photographing them. Failure to align each picture correctly would result in an unusable end product.

The colour image above is a Polaroid that would at the time have been placed in front of a TV camera and shown on air.

Anyone who has ever taken a colour photograph should salute Clerk Maxwell. He maybe best remembered for his work on electromagnetism but for photographers his work on colour theory stands as a high point.

Update, 09:20, 19 May: In response to the question below from Nilton Quoirin (comment 5). I'm not actually sure who took this picture of the assassination attempt. It is simply credited to the White House and we would have obtained it at the time via the Associated Press.

The most well known sequence of pictures from the event was taken by Ron Edmonds of AP who won a Pulitzer Prize for his work.

You can see more colour pictures of the event in the Reagan Library archives and I believe you can see photographer Ron Edmonds to the right of this frame.

If anyone knows who took the official picture published above then let me know.