Visible light is only a small part of the electro-magnetic spectrum. Certain films and digital sensors are sensitive to other areas of the spectrum, specifically near-infrared light. In fact, most digital cameras have filters added to deliberately block infrared light so it doesn't affect images made with visible light.

The electro-magnetic spectrum. Visible light is just a tiny portion.

Infrared photography creates unique images capable of portraying things not normally visible to the human eye. Infrared images can be created as art but they also have industrial uses. Infrared rays are much better at passing through the earth's atmosphere. Many satellite images are thus infrared images.

Two images taken seconds apart. One is captured using visible light, the other with infrared light. Image by Volkan Yuksel. CC BY-SA 3.0.

As the information captured in infrared photography cannot be traditionally represented using visual light, it has to be transformed to some degree. Infrared images can either be mapped to black and white or to colour. In black and white images, there is a hugely noticeable tonal shift. Blues are represented as black while reds and greens become white. With colour images shot using film, infrared light becomes red, red becomes green and green becomes blue; digital infrared images have a lot more variance.

Shooting Infrared Images

There are three common ways to capture infrared images. The first is to use a film camera and an infrared film stock such as Kodak HIE. Although many infrared films are discontinued they can still be found for sale.

Second, you can use an infrared filter to block visible light from hitting your DSLR's sensor only allowing a small amount of infrared rays through. The problem with this method is that it leads to incredibly long shutter speeds so isn't suitable for many styles of photography.

The final option is to use a dedicated infrared camera. Some manufacturers, such as Phase One, offer them but the more common option is to have the infrared blocker removed from an old DSLR. This obviously voids the warranty and renders the camera unable to capture non-infrared images but it offers the best digital results.

Some Inspiration

Infrared photography can be hard to visualise without examples. To help you understand what infrared images look like I've gathered 25 great examples. There are a mix of images captured with digital and film cameras to show the full range of possibilities.

The Wyoming Horse Dream. Image by Greg Westfall. CC BY 2.0.

Catholic Church Near Crowheart, Wyoming. Image by Greg Westfall. CC BY 2.0.

I Dream of Zebras. Image by Greg Westfall. CC BY 2.0.

Every Picture Tells a Story. Image by Greg Westfall. CC BY 2.0.

All Saint's Episcopal Church, Fort Worth. Image by Greg Westfall. CC BY 2.0.

Then Everything Just Got Weird... Image by Greg Westfall. CC BY 2.0.

Saigon Zoo with infrared Ektachrome 1970. Image by Manhai. CC BY 2.0.

Izmailovo. Image by Alex Defender. Public Domain.

Kodak HIE 10. Image by Anthony Shepherd.

Tilted Infratrees.Image by Alex Defender. Public Domain.

Madison Square Park Infrared. Image by Abe Bingham. CC BY 2.0.

The Weed is Growing Tall. Image by Zheng. Public Domain.

Wrapping Up

Infrared photography is a pretty weird area of photography. It captivates some people while others just find it unappealing. If you've explored it, please share some of your results below. It's always great to see our reader's images.