Aerial Perspective: The Staying Power of Film
Professional Surveyor Magazine - June 2012
By Richard J. Breitlow, CP
Unlike the consumer photographic market that quickly embraced the digital revolution, many industrial markets continue to see advantages in film. Film is still used extensively in the printed circuit board industry. The healthcare industry relies heavily on film x-rays, and aircraft manufacturers use film to create large tooling templates. The aviation industry uses non-destructive testing film to detect hairline fractures caused by metal fatigue, while cine and microfilm products also remain in demand.
Despite years of repeated proclamations that “film is dead,” film is still rolling off the production lines at Agfa Materials Corporation
for use in aerial mapping cameras around the world. The staying power of aerial film, in particular, is aligned with its unparalleled accuracy, low cost, ease of storage, and archival superiority.
Film cameras still set the standard in terms of overall footprint (area of coverage) and vertical accuracy as determined by height-to-base ratio. Most digital cameras cannot match the vertical accuracy achieved with the 1.67 H/b ratio of the standard 9” x 9” film camera without sacrificing area of coverage. The need for vertical accuracy is one reason many companies still prefer to use film cameras for large-scale engineering design projects. The superior height-to-base ratio of film cameras enables flight crews to fly at higher and more desirable altitudes without losing the vertical accuracy needed for the required contour intervals. Likewise, many airport mapping projects are still flown with film cameras to meet similar objectives.
In many cases, standard mapping accuracy specifications and other requirements for the deliverables can be met with film acquisition, at significant cost savings. For example, the Natural Resources Conservation Service recently compared film to digital for their National Resources Inventory program. They concluded film not only exceeded their technical specification requirements but remains the most economical and efficient option for them, citing significant cost savings. Various government agencies needlessly specify digital acquisition at times when film acquisition can meet all of the requirements for deliverables and simultaneously net considerable cost savings.
While lidar has proven to be highly accurate, the Federal Aviation Agency recently issued Flight Standards Information System (FSIMS) FAA Order 8900.1, Chg. 159, requiring lidar operators to obtain Standard Type Certificates (STCs) for many aircraft installations using Class IIIb and Class IV lasers. If this requirement remains in effect, the cost of STC compliance may need to be recouped via higher prices for lidar services. Film acquisition is expected to remain a cost-effective alternative in the marketplace.
Film has always been easy to store, without risk of lost data. Put the film in the can. Put the can on the shelf. In contrast, storage of digital data has become an ongoing challange of lost data, migrating files, back-ups, external drives, and servers.
American National Standards Institute specifications require film to be archival for 500 years. Digital imagery must regularly be migrated to new storage media and must be compatible with software and hardware as they, too, evolve. No digital media comes close to the archival superiority of film, and it costs practically nothing to store film for hundreds of years.
Technology and Film
Advances in technology made in one product line can sometimes benefit other product lines, even in different business groups. For example, new technology used to produce extremely fine-grain and high-resolution microfilm is being incorporated into a new Agfa black and white diapositive material, P3pHR, with higher resolution than the now-discontinued P3p.
Similarly, Agfa recently filled defense needs for medium- to high-altitude aerial reconnaissance films by introducing Aviphot Pan 20 and Pan 40. These films have very high resolution and are coated onto a thinner transparent polyester base, allowing more film to be wound onto spools and cores. Like other Agfa black and white aerial films, these have spectral sensitivity up to 750nm for superior haze penetration and gradation.
The clear base, strength, and dimensional stability of aerial mapping films are the same characteristics desired for “range films” used in high-speed cameras for military weapons testing. Film cameras mounted in launch area theodolites are used to accurately record azimuth and trajectory information for tracking missile launches.
In many cases, aerial photographs are desired in court proceedings. A photographic image captured on film is considered a legal document around the world because it cannot be easily modified. A digital image can easily be enhanced or manipulated in any number of ways and cannot be used as a legal document unless it can be proven to be representative of the original image.
Last year, USGS reversed its decision to close the Optical Science Lab in Reston, Virginia, used to calibrate aerial film cameras, and proceeded with the procurement of a sufficient number of glass plates to continue film camera calibrations for years to come. When USGS first announced its intention to close the Optical Science Lab at the 2011 ASPRS conference, feedback from conference attendees, various mapping companies, departments of transportation, government agencies and individuals was negative. All affected parties mounted strong opposition to the announced closure plans. The message was clear: there is still great demand for the use of film cameras, and the decision by USGS to discontinue calibration services was premature and needed to be reversed.
The bottom line is there are advantages and disadvantages to both film and digital acquisition. At Agfa Materials Corporation, the demand for film continues to be strong, and sales are steady. We anticipate strength in sales in coming years and plan to continue to support the market. The market is, and will remain, the driving force.
Richard J. Breitlow, CP (ASPRS) is with Agfa Materials Corporation, headquartered in Goose Creek, South Carolina, with parent corporation Agfa Gevaert N.V. in Mortsel, Belgium.
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