This "color" infrared image was obtained using the 2MASS three-band survey camera. The camera produces simultaneous images in the J (1.2 micron wavelength), H (1.6 micron), and Ks (2.2 micron) photometric bands. These three images were combined by assigning blue to the 1.2 micron image, green to the 1.6 micron image, and red to the 2.2 micron image (i.e. longer wavelengths equal redder colors, just as is the case for visible light). Since I am warm, my skin glows brightly at 2.2 microns -- thus my red skin color. I have a cold nose and cold fingers, however. Human skin is quite non-reflective at these wavelengths, so my cool skin appears nearly black in this image.
The color image is composed of the three images below. In order, they are J (1.2 microns), H (1.6 microns), and Ks (2.2 microns).
Click here for a larger jpeg format image of the color image above.
This image was obtained using the NICMASS infrared camera. A single small lens relayed the image through an infrared filter that permits only light with a wavelength of 2.2 microns (2200 nanometers, or 22,000 Angstroms) to reach the infrared detector array. This "color" of light is invisible to the human eye. This wavelength is approximately 4 times greater than the wavelengths of light that the eye typically detects. Most everything humans see with their eyes is seen via reflected light with the exception of self-luminous sources of light like the Sun and incandescent light bulbs. The Sun and light bulb filaments glow because they are hot. The glow produced by hot objects is called "blackbody radiation." The brightness and color of hot glowing objects is dictated by their temperature. The Sun has a temperature of 6000 degrees and glows "white-hot", emitting most of its light at a wavelength of 0.5 micron (the green part of the spectrum). Cooler objects emit most of their radiation at longer wavelengths. At room temperature all objects glow predominantly at infrared wavelengths. The picture you see above was obtained in a darkened room and shows that I am glowing at infrared wavelengths. The hotter any point in the picture is, the brighter the glow.