Infrared photography captures the light spectrum outside of what the human eye can see. The visible light that we can see measures between 400-700 nanometers, whereas infrared can detect wavelengths between 700-1000 nanometers, making the invisible visible.
Infrared photography has historically had many applications including astronomy, many kinds of pollution surveillance as well as forensics and medical photography. When photographing human beings, infrared illuminates the first few layers of skin and can reveal the veins. It has been used to map the veins, and also to detect the presence of any abnormalities or tumours in the body.
These black and white images of children in London were taken with a camera converted to infrared. In some of the images the veins are present, making the invisible visible and highlighting the vulnerability of all children to the air pollution that runs through their veins.