NTSB hosts accident photography course

 - October 16, 2006, 7:22 AM

Tell Sandy Weiss that his photos are plain, and he’ll thank you for the compliment.

“Good composition is desired and mandated in aesthetic photography,” said Weiss, an instructor for the NTSB’s course in accident site photography and a private investigator for StrataMetrics, an accident reconstruction firm. “In evidence photography, composition is a distant second to content.

“If the photographs do not portray a reasonable representation of the evidence, they are useless,” continued Weiss. “Making evidence compositions pleasing to the eye is unnecessary.”

The format of the accident site photography course at the Board’s academy was partly presentation and partly field exercise in the Academy courtyard, which resembles a sculpture garden of wreckage. Bins full of torn wings, charred engines and bent props sit beside derailed freight cars, shredded pipeline and mangled watercraft.

Although the primary audience for the course is accident investigators, the course is open to anyone who wants to take it, including business aviation flight department staff. The 25 students enrolled in the course I attended ranged from NTSB staff to investigators and pilots from Boeing Commercial Airplane, Hawaiian Airlines and the U.S. Air Force.

The purpose of the course is to teach students protocols for documenting and storing images of any accident site, in the most reliable and useful format. While few flight department staff members will document an accident scene, the course has useful applications for flight departments trying to document their fleets for legal or insurance purposes and trying to maintain their electronic documentation.

Flight department staff can apply the same techniques accident investigators use to document the history of the company’s fleet. Photographs can aid flight departments in determining the safest way to stow galley items, selecting a finish for cabinets and carpets or documenting incidents such as a minor breakage or bruise.

Weiss emphasized that the goal of accident site photography is different from the goal of personal photography: to minimize distortion and maximize the informational content, beginning with the correct angle and point of view. The right subject and quality of images will authentically re-create a scene for analysis, whether for internal use or for a court of law.

“Any 10-year-old can shoot what he sees,” said Weiss. “In storytelling, photographers are not documenting something that’s lying there. They’re trying to document why it’s lying there.”

The difficulty for both NTSB and flight department employees, he suggested, is external pressures. An NTSB accident site photographer, he said, is “a slave to the weather and the need to perform in any type of environment or lighting, while being pushed by law enforcement with time constraints,” he explained.

Flight department staff documenting even a minor incident also encounter time constraints. An aircraft may need to be returned to service, sent for cleaning, refueling or maintenance, all during minimal AOG time.

Equipment Management

Equipment was one topic of discussion at the one-day seminar. While professional accident site photographers have access to an array of the latest equipment, flight departments may be limited to one camera because of budget constraints. The ideal one-camera solution, said Weiss, is a reflex camera, with a macro-capable lens manufactured specifically for that camera. Reflex cameras let photographers compose through the lens, and are superior unless safety goggles or protective gear restrict view. Macro-lenses allow close focus and render images of at least half life size. Though the NTSB does not recommend specific brands and models, one example that fits the standard is a Nikon D100 with its 60 mm macro lens.

The course also explains the appropriate format for taking digital images. Ideally, photographers will record digital images that will later be used for comparison purposes or analysis in the digital format called RAW. The RAW standard captures the full image data, meaning that the file remains uncompressed. The next best standard is TIFF. Finally, the average image taken for evidence may be saved in the JPEG format, but a JPEG file is compressed–the pixels are “sampled”–to save storage space. At professional levels of analysis, JPEG files can omit vital detail.

The photographer should capture every image at the camera’s highest setting for resolution and quality, and never at less than 1,280 by 960 pixels. Primary images direct from the camera should be burned to a secure media such as a CD-ROM. Any subsequent enhancement, for example “red-eye reduction,” should be applied only to a copy. If your images are for the courtroom, or for a contested insurance claim, you may need a fine enough grain of film, or high enough digital capability, to support a 40- by 60-inch enlargement.

In digital photography, that much detail consumes a lot of storage capacity. A student passed around one solution for the group to inspect–his Nixvue Vista portable hard drive, a device the size of two decks of cards. The gadget held his hundreds of RAW images at 10 megabytes apiece, amounting to some 27 gigabytes of critical data.

Be Prepared

Much of accident photography addresses an event that took place days, weeks or years ago, with the goal of re-creating that scene with precision. But effective photographers stock their kits and develop plans for the assignments that require a response within minutes.

Weiss advised that accident site photographers keep a trunk or the aircraft cargo hold packed with a “go-bag.” Though packed and padded, this bag should in turn be contained in an overpack against shock and temperature. Pros carry an ice chest, either of cheap foam or a plastic cooler.

A minimum list for the go-bag consists of gear to protect against hazardous fluids and abrasion such as gloves, rubber boots and outerwear; safety glasses large enough to fit over eyeglasses; a flashlight; a compass; spare batteries for every device; a cellphone; GPS unit; plastic bags for debris; a notepad and/or a personal digital assistant.

The bag might become a frequent flier. Cumulative effects of security scans on film are given, but there is no proof, yet, that airport X-ray and explosives detection machines can damage a digital memory card. But the intensity and type of detector used by the U.S. Postal Service can severely damage a flash memory device.

Interior cabin space is costly, but the extreme temperatures of a baggage hold can ruin a photographer’s work and equipment. Packing the bag in an ice chest, without ice, can be invaluable. The temperature in a vehicle trunk can reach 130 degrees F and melt the glue on camera lens fittings. Many think that “digital” means no mechanical parts, but that applies only to the memory card; the heat can liquify the lubricants on a digital camera. Heat can ruin film but has not yet been shown to ruin digital memory.

An ice chest can also protect against cold. Battery power fades quickly with cold. Keep cameras stored or against your body. If using film, let the camera warm to room temperature before rewinding; the film turns brittle and can snap or when processed the static charge can cause “lightning bolts” or streaks.

A steady camera is a must, but professionals disagree as to whether to carry a tripod. Photographers should simply be equipped to steady the camera while using a slow shutter speed. Most people cannot hold a camera below one-thirtieth of a second, for example, while shooting the interior of an aircraft.

On-site Photography

The course teaches how to approach the subject at the accident site. Begin with photographs of objects likely to be moved. Even with no injuries or immediate danger, the NTSB, fire marshal or law enforcement personnel may prevent access to property and equipment.

Place a scale near the object for reference, something of a known size and color. Some photographers carry a ruler, though a pen or anything you can carry back to the office will serve. Even a coin will work, though reference items with angles are preferable. Include a photograph of the subject against a structure that is unlikely to move or change shape. Stonework or a fire hydrant are good choices; trees, seasonal or temporary structures are not.

Include one photo without the scale in the frame, because it either blocks or appears to block some part of the scene. Investigators who have not included such a photo have been asked what they are hiding.

Weiss considers his course a success if students learn but a single point: use any kind of flash other than the one built in to the camera.

The flat flash atop the camera removes all highlight, shadow and contrast from the photographs. Weiss recommends an off-camera flash. Fine detail in aircraft metallic parts, such as a fracture or wrinkle, emerges only with off-camera flash. If the subject is small, place a flash card behind it to bounce enough light back to the flash sensor. In special applications, Weiss uses an ultraviolet light unit, which makes similar materials show differently in the final image.

Aircraft aluminum, engine blocks or cabin light filtered through polarized window glass are all well off the standard factory preset of a light meter, which registers any scene as reflecting 18 percent of the light. Rather than rely on the camera meter, gather readings with a handheld light meter, or at least lock the camera’s meter on the object and then back off to compose and snap the photo.

The course teaches photographers to approach the subject methodically, following a grid or in a spiral coverage pattern, working from the outside then moving in concentrically. Shoot all of the corners, not the “flats,” overlapping the previous photo from your next angle.

For most legal and insurance purposes, keep the zoom and fancy lenses in the bag, because they exaggerate or shrink the perspective. Instead, use one standard focal length. Simply vary the angle of view for different perspective. Hold the camera away from your eye for a moment to compare how the scene looks with unaided vision. A normal view doesn’t have to be perfect, but it does have to be consistent.

The course also instructs photographers how to maintain photographs that will be used for evidence for insurance or legal purposes. The Evidence Photographer’s International Council advises that to be admitted into evidence, “a photograph must be a fair and reasonably accurate representation of the subject portrayed.” Beyond capturing the image correctly, that means preserving its accuracy until use via a chain of custody.

Chain of Custody

A chain of custody means continuous control. If a digital presentation, for example, skips from image number 38 to image number 40 in the litigation world, “You’re going to get busted,” said Weiss.

The image-maintenance protocol and chain of custody that Weiss teaches for accident investigators provides a useful model for flight departments, FBOs and fractional operators who want to catalog their fleets. In addition to critical definitions and materials control, the protocol should ensure that digital images remain in a tamper-free state, and that untrained or unauthorized employees are not allowed access to the equipment or the archives.

Photographers should back up critical data on CD, keeping additional backups in multiple formats such as the original card, on a personal computer hard drive and on the company server. “Memory is cheap, so store everything you get,” summarized Weiss. Consider a multiple card reader device to manage the various flash cards held by employees.

A flight department should keep its database current with the photographer’s name, date of exposure, image quantity in each series and descriptive information as needed. If the department shares software and storage equipment, an image processing log should be assigned and limited to employees within their competency.

There’s no standard for labeling, filing or searching for digital file types, software codes or photo archives. Windows and Apple environments yield different file names and lengths. Original images should be kept in the unaltered, primary format, with data backed up daily or at least often, and for all but a few individuals be in a read-only, unalterable medium. Images should be true and accurate representations, with only basic processing for color balance, exposure and contrast.

In professional use, always deactivate the date-time stamp that comes standard on most digital cameras. Once burned to the image it cannot be removed, and its placement alters the purity of the image and hinders an expert review.

The NTSB Academy is five miles from Washington Dulles International Airport. Tuition for Advanced Accident Site Photography is $250, which includes materials, lunch and beverages. Students lacking basic photography skills should first complete Technical Photography. For courses and schedule, call (571) 223-3900, visit www.ntsb.gov/academy or  e-mail academy@ntsb.gov.