Monday, November 7, 2011
Faux Infrared From Any Digital File—11/07/11
Use Lightroom to make color pictures look like infrared B&W
|This Article Features Photo Zoom|
I've long used Photoshop's Channel Mixer when converting color images to black-and-white. The control provided by this approach makes most other b/w conversion methods look crude by comparison. When I started using Lightroom in my workflow last year, I began dabbling with black-and-white conversion methods in that program as well. In the Develop module is a control panel for Hue/Saturation/Lightness, Color and Black & White. This is the place where you exercise precise color control over your RAW images in Lightroom, and it's a great place to make black & white conversions as well.
By clicking on B&W in this panel, the image is converted to black & white and you're presented with eight color sliders, scaled from -100 to +100. These sliders work similarly to the channel mixer in Photoshop, but I find this approach a little more straightforward and intuitive. What's especially nice about these sliders is that they work in much the same way a color lens filter works when shooting with black & white film. Because most black & white film is panchromatic, meaning all colors of light register on the film (though rendered only in black & white), the use of a colored filter can block some colors and allow others to pass through, dramatically influencing the tones in a black & white photograph. For instance, a red filter placed over the lens when shooting black & white scenics will block out a lot of blue, rendering skies very dark and dramatic.
When working with infrared film, a red filter is also used. This time, though, it's used on a film that's sensitized only toward the red (and infrared, or very red) end of the spectrum. So this film already doesn't see much in the green and blue end of the spectrum. When you block out the visible reds in a scene, all that remains to pass through the filter is infrared, and so that's the only light that registers on film.
So getting back to that adjustment panel in Lightroom, you can see how adjusting eight different colors of light from a little to a lot can make a huge impact on the look of a black-and-white image. Slide the blue toggle from the middle to -100 and suddenly everything blue in a scene—like the sky—goes from light to dark. Slide the green toggle to +100 and suddenly everything green in a scene gets bright white. You can see how quickly this can get weird—which is exactly what most infrared images look like.
Additional adjustments to temperature and tint in the White Balance palette will also have an impact on the overall brightness of the image, and adjustments to contrast, brightness, fill light and recovery will also help boost or minimize the infrared drama. Adding grain via the Effects panel can also more accurately emulate actual infrared film.
Sure this approach isn't overly scientific, and it certainly doesn't match the precision of an actual infrared image when it comes to seeing actual infrared light. But if you're looking to mimic the feel of an infrared image because you like that surreal effect, I can't think of a simpler, and more effective way to approach it.