Thursday, 12 June 2014

Plugged In: Focusing on photo problem-solving

By Joe Kashi, for the Redoubt Reporter

Using the rights tools for the task is always more enjoyable and effective than using a wrench to hammer down a protruding nail. You may get the job done, after a fashion, but the results won’t be pretty, nor the process easy.

Over the past few weeks I’ve had to solve a few unexpected photo problems, successfully and easily when the right tools were available, and less successfully when improvising with whatever gear was then on hand. That’s a story for another day.

On a recent Saturday afternoon, I was asked to promptly photograph the just-completed “Paint the Kenai” public mural, “Kenai La Belle,” a major public art project spearheaded by Marcus Mueller of the Soldotna Rotary Club, in partnership with the Kenai Chamber of Commerce and Visitors Center and the Kenai Fine Arts Center. There were many entries, with the winning entry and its outdoor location decided by community vote.

That very large, 12-foot-by-24-foot mural, designed by Kenai artist Fanny Ryland and destined for the exterior of the Kenai Municipal Airport terminal, was painted and assembled by community volunteers in Blazy Construction’s shop. You can get a better sense of this lovely public art, its imposing size and the scope of the community effort at the Paint The Kenai page on Facebook.

The mural needed to be moved quickly to make way for Blazy Construction’s summer work, so I had less than an hour’s notice after completion. Luckily, that was enough time to head to my office and get what I needed.

When I arrived at Blazy’s shop, I immediately noticed three significantly complicating factors — the assembled mural was indeed huge, with intricate patterns and striking colors that required accurate reproduction, the lighting was complicated and a large vertical pipe with many irregularly protruding valves ran floor to ceiling just in front of the mural’s center as it then hung, blocking any straight-on photos.

The assembled mural’s great size and the tight quarters clearly indicated that a superwide-angle lens was required to capture its entirety. Normally, using a superwide-angle lens results in very obvious horizontal and vertical distortion unless the axis of the camera and lens are positioned in the dead center of the scene and aimed exactly perpendicular to the center. That’s not feasible when so close to such a large work in very tight quarters.

Then there’s that large white pipe and its protruding valves obscuring the mural’s center. Rather obviously, “Photoshopping” out the pipe was not feasible. Its outline was much too complicated and, in any event, the mural did not have the right kind of repeating details that could be copied into that area with correct size and perspective.

That large pipe also meant that the floodlights on the balcony could not be used to light the scene — they would cast dark shadows of the pipe onto the mural, causing other problems. We had to use natural light, but the only natural light in this now-dark shop area came from some opened garage doors that lit the left side of the mural fairly brightly, while dropping off to quite dim lighting on the right side, 24 feet away. To complicate matters even further, that natural light was not direct sunlight with its normal color balance, but the cool-colored light of the blue sky. Uncorrected, such lighting would result in a photo with an inaccurate, bluish overall color, an unattractive result for this intricately colored and detailed community project.

Using my Pentax K-3 digital SLR and a 15-mm Pentax Limited ultrawide-angle lens, I positioned myself off-center about 6 or 7 feet from the mural’s front and to the left of the pipe, tilting the camera to include the entire large mural within a single exposure.

Naturally, the vertical and horizontal distortion was severe, with both the top and bottom angling together to form a wedge-shaped item rather than the correct rectangular shape. That’s inevitable whenever photographing any square or rectangular item from an angle, with more extreme angles resulting in more extreme distortion.

Using any film camera, except possibly a large-format view camera, that distortion was not correctable. However, it’s easy to fix with the right digital tools. In this instance, the distortion was more severe than readily correctable using Adobe Photoshop or Lightroom, so I turned to a fairly inexpensive, English-language program made in France, DXO Viewpoint. I was able to get good but distorted exposures within a few minutes, knowing that I could easily correct the distorted image to perfect perspective using DXO Viewpoint.

That fixed the problem of getting a correctly rendered image, but the lighting was still a problem, not only too blue but also varying greatly from one edge to the other. Fixing the color balance was easy using an X-Rite Color-checker Passport to make a custom profile for that camera under those lighting conditions. That custom profile would then be used in Photoshop or Lightroom to better approximate correct color. In addition, I hung a “Spyder-Cube” white balance and exposure reference on the left side of the frame. Including that standardized reference hardware allowed me to correct color balance and base exposure for the bluish light in two quick operations.

At this point I had a properly rectangular and color-balanced image of the entire mural without the offending pipe, but the exposure was highly imbalanced from left to right, and the strong side lighting highlighted the edges of several joints where various 4-by-8-foot panels joined. Again, current digital technology greatly eased the workload and facilitated a good-looking final result.

Using Lightroom’s graduated filter tool, I swept a gently varying exposure increase from the right side to the left edge, which more or less corrected the extreme exposure imbalance. A second graduated filter, decreasing the left side’s brightness, was swept from left to right. The net result of the two overlapping and opposing exposure filters resulted in a nicely balanced exposure across the entire image. Because I used RAW image files made with a Pentax K-3, a camera known for its very high resolution and excellent dynamic range, balancing the exposure from left to right was quick and easy. A few corrections with Lightroom’s “spot removal/heal” filter eliminated any distracting bright joint edges.

In this instance, it took more time to write about the problems and how to work around them than it took to actually make the final image. I wasn’t so lucky a week later when a very difficult photographic situation at the wedding of two friends caught me off guard, but that’s a topic for another day.

Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. He has published many articles about computer technology, law practice and digital photography in national media since 1990. Many of his technology and photography articles can be accessed through his website,

Article source:

Incoming search terms:

No comments:

Post a Comment