Infrared simply means near the outside the visible spectrum on the red end. It senses the reflected heat given off by the picture you’re taking. If you’re taking a landscape with people or animals in it, the landscape would be “feathery”and the body heat of the animals or people would be more prominent. If it’s sunny you’ll get a clearer image because more heat is reflected. Traditionally IR photography was taken with IR film loaded in the dark (try teaching that to a darkroom full of coeds), long exposures using a tripod, and tricky processing in the dark room. With the new Digital SLRs the process is faster and less cumbersome. However there is controversy on how much nuance you lose.
An Example of Tonal Ranges of SLR Digital Infrared
One thing you look for in a successful photo is the variations of tones (shades). Below is an excellent example of catching values from black to white and dynamic motion in Infrared. Using different tones pulls the eye across the page, compelling a response.
