Infrared Photography is created with film or a sensor that is sensitive to a spectrum of light that is not visible to the human eye. Infrared Photography was one creative tool I used to distinguish myself from other photographers, especially at weddings. Not many photographers in my day used infrared film for several reasons. Infrared film was expensive, challenging to handle, challenging to shoot, and challenging to develop. The film required handling in complete darkness, making roll changes on location not a very convenient option.
Camera meters are not calibrated for the infrared wavelength, and infrared light does not focus at the same point as visible light. Metering was mostly a guess, with liberal bracketing until I had enough experience to narrow the exposure settings. While an #87 or #89 filter gave more dramatic results, I used a #25 so I could actually see through the lens. Since I shot mostly weddings and portraits, I needed the flexibility to hand hold and move around. The results were dramatic enough, and my clients really enjoyed the Infrared Photography images.
Kodak HIE was the best choice for black and white Infrared film at the time with predictable results in the infrared wavelength (~750-900nm). I preloaded it into a vintage Olympus OM2N that I had since college, and shot a roll at daytime outdoor weddings, conditions permitting.
Much to my dismay, Kodak announced in November 2007 that it was discontinuing HIE due to lack of sales. I bought all I could find within my means, and I still have a roll in the refrigerator for sentimental value. For complete technical data from Kodak about HIE Infrared Film click here.
Rollei still makes an Infrared film, and Ilford makes an extended sensitivity film (SFX). There are also digital camera conversions that yield good results, or you could use Photoshop to simulate an Infrared Photography effect.