Infrared Photography: Images of Unseen Color

Photographs taken with infrared sensitive film can create drastic contrasting colors that create a unusual and unique image. They capture colors that are outside our own range of vision, offering a perspective changing experience.

How It Works

In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Usually an “infrared filter” is used; this lets infrared (IR) light pass through to the camera but blocks all or most of the visible light spectrum (and thus looks black or deep red).

When these filters are used together with infrared-sensitive film or sensors, very interesting “in-camera effects” can be obtained; false-color or black-and-white images with a dreamlike or sometimes lurid appearance known as the “Wood Effect.”

The effect is mainly caused by foliage (such as tree leaves and grass) strongly reflecting in the same way visible light is reflected from snow. Chlorophyll is transparent at these wavelengths and so does not block this reflectance (see Red edge). There is a small contribution from chlorophyll fluorescence, but this is extremely small and is not the real cause of the brightness seen in infrared photographs.


The other attributes of infrared photographs include very dark skies and penetration of atmospheric haze, caused by reduced Rayleigh scattering and Mie scattering, respectively, compared to visible light. The dark skies, in turn, result in less infrared light in shadows and dark reflections of those skies from water, and clouds will stand out strongly. These wavelengths also penetrate a few millimeters into skin and give a milky look to portraits, although eyes often look black.

History

Until the early 1900s, infrared photography was not possible because silver halide emulsions are not sensitive to infrared radiation without the addition of a dye to act as a color sensitizer. The first infrared photograph was published in 1910 by Robert W. Wood, who discovered the unusual color effects that now bear his name.
Wikipedia Infrared photography

Photos from naomifrost, capnsurly, hartleyphotography, spookygonk and btobin

Author: evad
David Sommers has been loving color as COLOURlovers' Blog Editor-in-Chief for the past two years. When he's not neck deep in a rainbow he's loving other things with The Post Family (http://thepostfamily.com/), a Chicago-based art blog, artist collective & gallery.