Saturday, March 29, 2014

Digital Enhancement of Infrared Images

My Before and After post has raised some concerns about the amount of digital enhancement used to create the “After” image below.

Before - out of camera, CNX2

After Image
Ansel Adams, the consummate darkroom specialist said, "You don't take a photograph, you make it."

As an infrared photographer, I agree wholeheartedly with his assessment. In IR photography, all colors are false and the "true" image is invisible to the naked eye.

One of the great things about IR photography is that there is no visual standard for a "right" or "wrong" photograph. Who among us can personally vouch for the accuracy of the visual representation of an invisible spectrum?  We cannot perceive the light that illuminates the scene, the IR reflections, or wavelength (color wheel) interactions. This frees us to take whatever poor approximation of the scene our cameras provide, and make something interesting with it. Some people do this with color, others with black and white. It's all valid.

This concept is liberating for the artist and disconcerting for the technician who wants to create a "perfect" or "natural-looking" IR photograph.

Yes, we can create similar images using a visual camera and digital manipulation, but the public will know the image is “faked” or “Photoshopped,” no matter how interesting the image may be.  By telling the viewer they are looking at an infrared image, the viewer can suspend disbelief and evaluate your image as an image.

Liberating indeed…

Wednesday, March 26, 2014

Post-Processing an Infrared Image - Step by Step

In this post, I will demonstrate how I approach my post-processing for IR photos. This photo was taken in Alpena Michigan at the Evergreen Cemetery. I used a Nikon D90 with a LifePixel Standard IR (720nm) conversion and a Nikkor 20mm AFD lens.  

The images on this page are pretty small. You can view larger versions by clicking on the image.  

Out of camera image.  NEF opened in Photoshop
This first image is straight out of the camera and converted to a JPG for this article. This is what the NEF image looks like when it is opened with Photoshop. All of these images started with the LifePixel preset white balance. 
Out of camera image. NEF opened in Capture NX2

The second image shows the same NEF opened with Nikon Capture NX2. The image looks different because CNX2 can read and apply the camera picture controls. My post on camera settings will give you my normal setup. This photo has more sharpness and contrast than the Photoshop image. This is the same image I see on the back of the camera.

White Balance set in Capture NX2

I set the white balance using CNX2 and saved the image as a TIFF. I normally do a channel swap at this point but I knew I did not want a blue sky for this image. 

Adobe Camera Raw Adjustments

I selected the TIFF in Adobe Bridge and opened it in Adobe Camera Raw. In ACR, I adjusted the recovery (5) to tone down the highlights, increased the blacks to 9, darkened the image by decreasing the brightness to -3. Contrast was 14, clarity 37, vibrance to 15 and saturation to 16. I opened the image as a copy in Photoshop.

Viveza 2 for structure and contrast.

Contrast and clarity adjustments can produce noise so I used the NIK Define 2 plug-in to clean it up a bit. (I used the default settings.)  I wanted the image to have more structure in the foreground and the sky so I used the NIK Viveza 2 plug in. Structure setting was 60%, contrast was 30%, and the shadow adjustment setting was -48%. Structure adjustments also add noise so I used the NIK Define 2 program again to reduce the noise artifacts.  

Color Efex Pro 2 Low Key Filter to add moodiness.
I wanted this image to be dark and moody so I used the NIK Color Efex Pro 2 plug-in and the low key filter. I adjusted the glow to zero, Standard Low Key to 22, Dynamic Low Key to 56%, and Saturation to 40%.

Final image after color adjustments and final tweaks.

Now it is time to adjust the color. I opened a levels adjustment layer and used the black point picker and chose a point on the foreground fence. I used the white point picker and chose the brightest point in the image. I moved the mid-tone slider a little to the right to darken the image further. I applied a hue and saturation layer to further tweak the color. 

Final tweaks included adjusting the brightness and contrast, a little dodging, and I cropped a little off the right side of the image. I signed the image using the copyright brush (see my post on that) and applied the final sharpening using Smart Sharpening (15%) in Photoshop.
My normal workflow for IR photos is as follows:

1.  White Balance in CNX2
2.  Channel swap (not on this image)
3.  Adjust contrast and structure
4.  Adjust lighting and mood
5.  Adjust color
6.  Final tweaks and sharpening,

Friday, March 14, 2014

Winter IR Photography

This is the fifth post in my series on what to do with your IR camera during the “off season.” 

In this post, I will talk about winter landscape photography.  Winter landscape photography is very similar to summer photography except that it is cold and battery life is much more limited.  I always keep a spare battery inside my coat where it will stay warm. This gives me more shots than a battery kept in my car, camera bag, or in an outside pocket. 
It is also important to protect your camera and lens when you bring them in from the cold. Warm moist (inside) air will condense on and in your cold camera gear when you bring it in from the outside.  This will introduce moisture into areas that should never get wet. To prolong camera life, I seal the camera and lens into a gallon-sized zip-loc bag before I bring it into the house. The camera and lens stay in the bag until they reach room temperature. 
I generally classify winter shooting into three types of photography – sunny day shooting, shooting under overcast skies, and the crazy business of shooting in nasty weather. 
Sunny day shooting is the most logical type of IR photography. During sunny days, IR light is plentiful, shutter speeds are short, and you don’t need a tripod for most shots. Clear blue skies produce nice dark IR skies that highlight any puffy clouds that may be in the scene. Sunny conditions also produce lots of glare, especially from the snow. This is where IR photographers have an advantage over other photographers because IR photographers deal with glare from grass and other vegetation all the time. The same approaches and settings you use to deal with vegetation glare work for snow glare. Using a lens shade is very important under these conditions to reduce lens flare.
Gallup Park, Ann Arbor Michigan - Infrared
My first sunny day photo was taken at Gallup Park in Ann Arbor, Michigan.  The skies were beautiful and the temperature was 1 degree below zero Fahrenheit.  I wore over-gloves with silk glove liners to keep my fingers from freezing to the camera. To take a photo, I removed the over-gloves and handled the camera with the silk gloves. My hands got cold very quickly but they did not stick to the camera.  This photo was taken with a D70s with a 720nm standard IR conversion. Most people would not realize that this is an IR shot because it looks almost “normal.”  The real challenge for this photo was to remove the blue cast from the snow after the channel swap. I used a Hue and Saturation adjustment layer to remove the color cast.
Evergreen Cemetery, Alpena Michigan - Infrared
The second sunny day photo was taken at the Evergreen Cemetery in Alpena, Michigan. It was another beautiful winter day with a temperature of about 20 degrees Fahrenheit.  This photo was taken using a D90 with a 590nm SuperColor conversion. The major challenge with this photo was dealing with the high contrast caused by bands of bright snow and darker shadow. I kept adjusting the camera until the histogram was acceptable and the “blinkies” (blown out areas) were under control. As before, I used a Hue and Saturation adjustment layer to remove the blue cast that remained after the channel swap.
Curran Michigan Gully - Infrared
The next two images were taken near Curran, Michigan using a SuperColor converted D90. As you can see from the first image, the day was extremely overcast and the sky acted like a giant soft box. There is very little shadow and almost no contrast in the snowy areas. The blue cast was removed from the snow as described previously and NIK Viveza 2 control points were used to give the nondescript sky some structure and contrast. 
Snowmobile Path, Curran Michigan - Infrared
The next photo was included to show how I attempted to make a featureless snowy foreground a little more interesting. To do this, I looked around for an area that had weeds poking up through the snow. In this case, I also found an area where snowmobiles had torn up the snow and the ground. My intention was to create an image that had an interesting foreground, a middle ground, and a background. The foreground is interesting but the rest of this photo is pretty boring.
Taking IR photos in nasty winter weather has many challenges - some obvious and some not. Personal safety and potential equipment damage are some of the obvious challenges and I am sure we all can come up with four or five other reasons why we shouldn't be wandering around with a camera during a winter storm. The less obvious challenges have to do with light.   
We all know that the world gets darker when a thick, snow-laden cloud bank is overhead.  This is a world with little contrast and no color. Only the closest objects have any hope of producing a sharp image.
IR light is highly variable under these conditions. IR light can sometimes fall off faster than the visible light during winter storms. This is important because the metering and exposure system in your converted camera uses visible light.  Your routine camera settings may not work and when you find a cool shot, you may need a tripod or insanely high ISO settings to bring it home. Even with all these negative aspects, taking photos during a winter storm can be rewarding for the reckless, foolhardy, and naive. 
Snowstorm in Grand Rapids Michigan - Infrared
This photo was taken in Grand Rapids Michigan during a snowstorm. I drove over from Ann Arbor to attend a photo workshop and arrived earlier than expected. This was a Saturday and we were in an old industrial area that was being converted to lofts and studios. I decided to take the IR camera for a walk in the storm. Did I mention reckless, foolhardy and naive? 

For this photo, I was standing on an iron bridge that spans the Grand River. The snow was falling like mad, I could not see a soul, and the steel-gray water below looked awfully cold. I leaned against one of the steel uprights to steady the camera and shot back along the path I had just traveled. This is a color IR photo using a D90 with a standard 720nm IR conversion. I set the white balance with Nikon Capture NX2 but did not perform a channel swap. I liked the little bit of sepia coloration left over from the white balancing. It made the image look like vintage photo.
Iron Bridge, Grand Rapids, Michigan - Infrared
The final photo shows the same iron bridge from the roadway. As I was standing in the middle of the road, a snow plow came around the corner behind me.  I don’t know who was more surprised!  I got out of his way and captured the image after he left the scene. Once again, there was no channel swap. I did not like the sepia tone on this one so I converted it to black and white.
I hope I have demonstrated that you can take interesting landscape photos in the winter and maybe next year, your IR camera will join you on some winter excursions.