One of the most charming contrasting color effects you can get in photography is by using infrared. An easy way to understand near-infrared light is to think of it as the color of the rainbow next to red, a color that is invisible to the human eye. But near-infrared is not the same as thermal imaging.
Because everyday objects reflect infrared in proportions that differ sharply from that of visible light, the tonal relationships are wildly unexpected. Such near-infrared techniques used in photography give subjects an exotic, antique look. Green vegetation becomes white, whereas human skin becomes pale and ghostly. The resulting images look alien.
Digital cameras use CCD and other similar sensors to capture infrared images. Although all digital cameras available on the market are sensitive to infrared light, they are equipped with infrared-blocking filters. The main reason for this is that consumer cameras are designed to capture visible light. But sometimes these filters are used together, giving very interesting in-camera effects like false color, wood effects etc.