Fire infra-red photograph

There is a spectrum of light beyond that which can be seen by human eyes, the so-called “infrared” region. Credit goes to the German astronomer William Herschel, who found it while researching what glass color was best for transmitting light without heat. Herschel used a prism to split sunlight into component colors, measuring the temperatures of each one. To his surprise, temperatures were the hottest at a region beyond red, the highest visible color on the spectrum. He called it “invisible light”, and it needed the better part of century to come to common use.

On this day, October 7, in 1931 the Eastman Kodak Research Laboratories in Rochester, New York took the first infrared photograph. A group of people standing in pitch darkness were visible through infrared light, and Kodak proved they could be photographed using their technique.

The most obvious use for infrared imaging is artistic — with the colors from the infrared spectrum translated into visible light, the results are often dramatic: white foliage under black skies. As well, infrared photography has proved useful in medicine, in nature observations (for example, in dark where a flash is imprudent, and of course in military — the night vision technology of today is largely based on scanning the infrared spectrum).