Did you know that your digital or video camera can take pictures by “light” you cannot see? It is possible to use infrared illuminators but I will mostly discuss daylight photography here. I have tried this with two different digital cameras and it works. I understand that all digital cameras have an internal infrared blocking filter but many allow enough infrared will get through to make photography feasible. In normal use the infrared that gets through doesn't affect the color balance. When you shoot with the visible light filtered out, only a gray scale picture is possible with everyday digital cameras. That's because all three color sensors respond to the infrared. Three cameras I am familiar with have methods described here. The Canon A540 and the Panasonic PV-L652 work well as described in the next 3 paragraphs. The Nikon D90 does not. Customized infrared digital cameras have been described in Popular Photography.

The eye sees radiations with a wavelength of 400 to 700 nanometers, formerly called millimicrons. The visible red spectrum is about 600 to 700 nanometers. Electronic sensors can also respond to wavelengths to at least 900 nanometers (0.9 micrometers), as can color or black & white infrared films. This part of the spectrum is known as the near or optical infrared.

The infrared rendition of plants and the sky are unusual. Chlorophyll reflects a great deal of the near infrared radiation your electronic camera will record, and most plants will look white. The sky will look black. There will be some haze reduction on sunny days. With the Canon A540 and Panasonic PV-L652, you need to use a filter, such as the Kodak or Tiffen no. 88A to remove the visible light. The no. 88A cuts off below 720 nm. This filter may also be labeled "R72".

You may also use a number 87 or "R76" filter which cuts off below 760 nm. You may need to use a tripod with the no. 87 because of shutter speeds longer than 1/30 of a second.  NEVER LOOK AT THE SUN THROUGH THESE FILTERS EVEN THOUGH THEY ARE NEARLY BLACK.

With the Nikon D90, only a limited infrared effect is possible because an internal filter cuts off nearly all infrared above 700 nanometers. You may try an 89B or "R70" filter, if one can be found, and you will need a tripod and long exposures. The R72 filter may also be tried, with very long exposures.

I have seen filters on eBay that cut off below 900 to 960 nm. These are unlikely to improve haze penetration, in my opinion. Also, in my opinion, they will result in less sharp photos due to long exposures and lower resolution at these long wavelengths. And, ordinary camera lenses are not designed for infrared away from the visible spectrum, so there is an increase in unsharpness due to lens aberrations. The focus shift correction will be greater also, described three paragraphs below. All that said, however, you may want to experiment in seeing the world by these invisible radiations.

It can be interesting also to find out just how far into the infrared ordinary digital sensors can see. Kodak has made scientific films that are sensitive to 1400 nm. Infrared spectral biochemical analysis devices for laboratories work at much longer wavelengths of about 2 to 16 micrometers (2,000 to 16,000 nm).

With biochemical analysis, the substance being examined is scanned for transmission through these longer wavelengths. Each compound gives a "fingerprint" response through the spectrum. You may remember the substance Krebiozen from the 1960s which was touted as a cancer cure. As I recall it was found, by infrared, to be creatine, or creatinine, a substance commonly found in the body and useless in treating cancer.

Have your camera shop assist you in fitting the filter to your camera. A custom 52mm filter holder is made for the A540. Most Nikon SLR lenses accept 52mm filters directly. Set your electronic camera to ISO/ASA 400 if possible, and set it to manual focus at 20 feet or so. This gives a slight focus shift necessary with infrared. The resulting image will have no color, but will be pinkish grey-tone in an electronic camera. In your photo editor, you will likely want to convert the image to black & white. It is normal for infrared pictures to be less sharp than those with visible light.

For color infrared film pictures, write me. Infrared Ektachrome slide film may have had a name change recently. It is a false-color, high contrast film that records the visible green and red, and the near infrared parts of the spectrum. It can be developed by the same process as most other slide films. It is used with a yellow number 12 filter. A CC30B filter may also be needed to reduce visible exposure relative to infrared. Otherwise pictures may have a strong blue-green color cast. Photos of trees look something like normal autumn photos. Color infrared film is useful in aerial forest photography to detect the spread of disease.

A black and white 35mm infrared film called Kodak High Speed Infrared film may still be available. Years ago, Gevaert of Belgium made 120 size infrared roll film. These films were used with red or infrared filters. That is because there was some sensitivity to blue and green visible light. They were also sensitive to red and infrared to about 900 nm.

It is also possible to photograph heated objects between 482 F and 932 F in the dark with infrared film or digital cameras that respond as the Canon and Panasonic above  do. This requires time exposures. Objects below 482 F require special cameras that work at long IR wavelengths of 5 to 15 micrometers. Objects above 932 F emit visible light and can be photographed with normal film or any digital camera.

Here are 4 samples taken with the Canon A540 point-and-shoot camera. Use your browser's return button to return from photos here.

These were taken with a Kodak No. 88A gelatin filter.

Infrared no. 1

Infrared no. 2

Infrared no. 3

Infrared no. 4

There are three more infrared photos in the Mt. Rainier pictures. They were taken with an R76 filter.