Wednesday, November 20, 2013

Infrared Leaves Don't Have to be White

Traditional IR photo. Ann Arbor, Michigan.
The classic infrared landscape photo is a scene where the sky is dark and the leaves are white. Sometimes this convention is followed because the photographer chose to convert the image to black and white, sometimes this convention makes sense from an artistic perspective, and sometimes we see a classic IR rendering because the photographer is trying to create a "proper" infrared photograph. 

I firmly believe that there are no "proper" IR photographs. IR light is by definition, invisible to our eye. The IR images we "see" in photos have  all been converted to visible light photos by some arbitrary process. This conversion may be through chemically induced changes in a film emulsion or it may be the results of a bining algorithm used by your camera's image processor. If you look at the RGB histogram on the back of your camera, you will see that the processor has placed some of the incoming IR light into the blue and green bins even though these wavelengths are blocked by the IR filter. What is proper or natural about that? 

Cascade of light through the leaves. Ann Arbor, MI.
Some photographers will argue that black and white IR photos are the only "proper" representations of the actual infrared image. I say, "Phooey!" on that argument.  The entire visible spectrum, from blue to red, exists within a 400nm wavelength range (~300 to 700nm).  When fitted with a 720nm filter, your camera's sensor can detect about the same wavelength spread. If my eyes were silicon sensors, I would see about the same number of IR colors as my real eyes see in the visible spectrum. So black and white isn't the "proper" way to represent infrared light either.

The purpose of this little tirade is to point out that there is no "proper" way to present an infrared photograph. There is only what you like and dislike and what others like and dislike. This observation can be disconcerting or liberating, depending upon your disposition. Vive la Liberté!  After all, who's going to know if you get the colors wrong?  

Tone-on-tone leaves against block wall. Ann Arbor, MI
So back to the title of this post "Infrared Leaves Don't Have to be White."  In full light, your camera will render leaves as white but that does not mean that you must let them stay that way. Using the tint and color swap sliders can sometimes produce images that are pleasing to view and look very different from images posted by others. Not every image needs a color swap and some don't need color balancing, either. The image is the image, but the colors can be anything that makes you happy.

The second photo in this post is an image of the light streaming through the trees in my neighborhood.  There was no channel swap. The leaves in the image are white, brown, and red. The background is a deep red. To me, the net effect is a cascade of light against a dark background. It is a busy photo but it made me happy.

Crow silhouette. Ann Arbor, Michigan.
The third photo did not get a channel swap either. This photo was taken using the LifePixel preset white balance. The result was a tone-on-tone image of the leaves and the little flowers were white. It really did not need much post-processing.

The fourth image is a silhouette of a crow. This one got a channel swap but I used the sliders to make the leaves yellow and yellow-green. I thought this contrasted nicely with the black crow silhouette.

Infrared photography is especially well suited for artists who have moved beyond the mere taking of pictures into the realm of making pictures. I encourage you to make something happen in your infrared photography.  No apologies. No excuses. No limits!    


Sunday, November 10, 2013

Creative IR Lighting - Infrared Light Painting

This is the third post about things you can do with your infrared camera during the “off season.” My previous posts about candlelight IR photography can be found here and here.

Antique oscillating GE fan circa 1940 or 1941.
Light painting is a technique where the photographer literally paints the object with light during a single long exposure. This technique is often used when the photographer cannot get the lighting they want with flashes, strobes, or natural light. The creative advantage of light painting is that it allows the photographer to selectively wrap light around the subject and enhance the image in ways that would not be otherwise possible. 

Light painting also adds a measure of creative uncertainty to the image and no two light paintings will look the same. The shape of the light beam, how you move it, and how close the light is to the subject have profound effects on the ultimate exposure. This will delight you or drive you nuts!  For the sake of full disclosure, I must also warn you that light painting is an experimental process that requires dedication, patience, and perseverance. The fan photo shown here took about 20 tries before I got the lighting the way I wanted it. 

How to Get Started

First off, start small.  Photographing small interesting subjects in a dark room gives you fewer things worry about at first.  This requires minimal or no additional investment in gear.  Basically, you need an infrared converted camera that has the ability to hold the shutter open for extended periods, a sturdy tripod, and a flashlight.  The flashlight must have an incandescent bulb because LED flashlights generate very little IR light. Light shapers can be made with gaffer’s tape, cardboard, and aluminum foil.
  • A dark room is important because you will be using long exposure times.  Even an LED light will make a noticeable contribution to the exposure with a 20 second exposure.
  • The movement of the light is extremely important.  You should not hold the light in one position because the light quality will be flat and harsh.  I generally try to keep the light moving even if I am painting a small area.  
  • Controlling the angle of the light is very important, both for creative purposes, but also because light spill onto the table or other objects can create undesired bright spots. 
Light painting is like learning a new dance. During the painting process, you are trying to reproduce the movements that produced the desired lighting and find correct movements to address the lighting that wasn’t quite right. When the shutter opens, I find myself counting as I move; i.e., two seconds on this area at this angle, three on the next, step back for 5 seconds to introduce background lighting.

Camera Settings
  •  ISO:  Base ISO
  • WB:  I use the LifePixel preset
  • Long Exposure Noise Reduction:   ON
  • Exposure Delay:  ON*
  • Use a remote release cable or use the timer function to open the shutter*
  • Manual mode
  • Shutter speed:  10 or 20 seconds
  • Aperture:  f/22 or higher to allow time for painting – this will be determined empirically.
*These settings are not strictly necessary in this example because any initial vibrations will occur when the room is dark, but it is a good practice for tabletop work. 

Procedure
  1. Set the camera up on a sturdy tripod or other support.
  2. Once your general settings (above) have been established, take a photo without turning on the flashlight.  You want to check for any unexpected light sources that will pollute the scene.  Examine the resulting photo on a real monitor (not the LCD on the back of the camera) to make sure everything is black.
  3. If you use autofocus, focus the camera then switch to manual focus.  Autofocus will hunt in the dark.  For critical focusing, use Live View (zoomed in on the area you want to be sharpest) and focus manually.  Be sure to switch back to manual focus.
  4. Click the shutter turn on the flashlight, and experiment.
Antique Underwood typewriter with sepia overlay.
Final Thoughts
Photography is all about the light.  While interesting subjects and colors help to make an outstanding photo, lighting can make those same subjects boring or exciting. With light painting, you control all the light and you can readily see how the direction, intensity, and character of the light affects the final image. Light painting is a great learning tool and a fun way to spend a winter evening. 

Shooting Information

Antique Fan.  The fan was placed on the edge of a table and photographed with an IR-converted Nikon D90 (590nm SuperColor conversion from LifePixel) and a Nikkor 20mm f/2.8 AF-D lens.  Lighting was provided by a small MagLight flashlight. I constructed a snoot with aluminum foil and gaffer tape to give a directional light beam with minimum light spill. The shutter was open for 20 seconds at f/22, -1EV, ISO 200. I had to use the smallest f/stop to keep the exposure at 20 seconds.  A sepia overlay was added in post-production to even out the tones.

Underwood Typewriter.  The typewriter was placed on the edge of the table and photographed with an IR-converted (720nm IR Standard Conversion from LifePixel) D90 and a Nikkor 20mm f/2.8 AF-D lens. Lighting was provided by a Mini MagLight.  I constructed a snoot for the flashlight using aluminum foil and gaffer tape.  I wanted the “brush” to be a thin line of light with minimum light spill. The shutter was open for 20 seconds at f/16, -3.3EV, ISO 200. A light sepia overlay was added in post-production to even out the tones.