Infrared

The earth is illuminated with a broad spectrum of electromagnetic radiation (light) - ranging from gamma rays to radio waves - almost all of which is invisible to us. The tiny fraction of the light spectrum that our eyes can detect triggers electrical signals in the light-sensitive neurons in our eyes. Depending on the types and location of neurons stimulated, our brain interprets these electrical signals to create what we perceive as images and “colors”. A digital camera works in a similar fashion, except that its the camera’s processor and software algorithm that interprets electrical signals from the pixels in the sensor to determine intensity and color information that is stored in a digital image file.

Infrared light is just beyond the red end of the human visible spectrum. Although some animals can see in the infrared, our eyes cannot. As a result, our brains lack the ability to interpret a “color” for infrared light. But by using a camera suitably modified to detect infrared light, and filters to block visible light from the sensor, it is possible to create photographs showing how the world would look in the infrared. Because our brains do not understand “colors” in the infrared, we see the images as black and white (light and no light). Many photographers use filters that allow some wavelengths of visible light to reach the sensor, or subsequently modify their infrared images by adding false colors to various image elements. These false color images can be artistically interesting, even beautiful, but they do not accurately reflect a true infrared image. Most of the images in this section show only what the camera saw at infrared wavelengths.