History of Aerial Photography Platforms and their Uses

Introduction

Aerial Photography, Aerial Mapping, Aerial Survey, Remote Sensing or however it is called serves many different purposes.  The basic tools required to carry out an aerial photography mission consist of an aerial platform and a way to capture the imagery.  These tools usually consist of an airplane, and a camera.  Although airplanes are the most commonly used platform, there are other methods used to achieve basically the same result.  Some of these other methods include balloons, kites, rockets, airplanes, helicopters, satellites and multiple other unusual creations.  Many of these methods were creative solutions to a challenging problem, when airplanes and helicopters were not available.  Today, it is a lot easier to fly a mission with a helicopter or a fixed wing aircraft.  Using a fixed wing platform allows for a more thorough picture and has the ability to deliver higher quality images. 
When aerial photography was in its infancy, the tools used at the time were large bulky cameras and balloons.  In fact, the cameras were actually and are still called large format cameras.  Many of these cameras used a variety of plates that required a cocktail of toxic chemicals in a wet or dry format.  Often these plates were likely to be exposed to contaminants that would ruin the photo.  Throughout the development of camera technology, cameras became progressively smaller, lighter, easier to use, and photos became easier to develop.  Even though aerial reconnaissance was a high priority in World War One (WW I), it wasn’t until after the war that a camera suitable for aerial photography would be invented.  It was Sherman Fairchild’s intention “to create a camera shutter sandwiched between lenses, thereby reducing the significant image distortion previously hampering aerial photography and mapping” (Wikipedia; Sherman Fairchild).  Aerial mapping has come a long way since the French incarnation of a balloon and a camera and in many ways it is WW I is where aerial mapping really began to mature.

Balloons as a Platform
 
Throughout the late 1800’s many attempts at aerial photography were made, and largely failed.  Of the many forms of aerial photography that exist, the balloon as a platform was one of the first.  Although the photographs no longer exist, some of the first aerial images were captured by a Frenchman named Gaspard-Félix Tournachon more commonly known as Nadar.  Because he was using the wet process, Nadar often had difficulties in getting the images to develop correctly.  The wet plates he used in the camera would become contaminated with the hydrogen sulfides emitted from his balloon. This contamination caused the plates to fog.  Though most of Nadar’s aerial photography experiments failed, he did succeed a number of times, albeit by accident.  In an attempt to conserve fuel, Nadar closed off the vent to the balloon and the balloon released fewer sulfides.  By closing the vent, this allowed Nadar’s photos to be less obscured and provided for greater clarity in the photographic details.  Photographic evidence of his success has unfortunately been lost over time. 
As sad as it is that Nadar’s photographs do not currently exist, the first known aerial photos still in existence were taken only a few years later by James Wallace Black. Like Nadar, Black had his fair share of problems.  In an effort to make the balloon more stable, Black’s balloon was tethered to the ground.  This proved difficult in that the wind made the photography hard.  By this time many photographers had converted from wet plate technology to dry plate processes.  Even though technology had moved from the wet plate to the dry plate, photography was still a slow moving art in the sense that if there was a lot of movement then the exposure wouldn’t turn out very well. 
Not long after Black had shown how useful balloons could be, “balloons were used for surveillance and reconnaissance during the Civil War for both sides, [with] the Union side invest[ing] heavily in their development. The ability to locate troops and assess their numbers quickly became a very important capability, but it is not known if a photograph from a balloon was ever taken because to date no vertical or oblique aerial photography captured by balloons from the Civil War period have been found” (US War Balloon Corps.).  This trend to use balloons for military use gave the advantage of high ground.  In fact, “the French had first used balloons for reconnaissance during the Napoleonic wars and later in the Franco-Prussian War. So aerial reconnaissance was a strategy that was familiar to them…” (Century of Flight). 

Kite Aerial Photography

Even as far back as Greek mythology will take us, mankind has been seeking ways to fly.  This innate desire to harness the wind is manifested as far back as the kite.  Probably one of the best known Chinese inventions, the kite has rendered itself not only as an item of beauty, but also an item of utility.  One of the challenges that faces kite aerial photography (KAP) is the ability to make a camera airborne and acquiring a stable image.  M. Arthur Batut, one of the earliest practitioners of KAP accomplished this by attaching a camera directly to the kite.  “The camera attached directly to the kite, had an altimeter that encoded the exposure altitude on the film allowing scaling of the image. A slow burning fuse, responding to a rubber band-driven device, actuated the shutter within a few minutes after the kite was launched. A small flag dropped once the shutter was released to indicate that it was time to bring down the kite“(History of Remote Sensing, Aerial Photography).  Other KAP practitioners developed their own methods for capturing aerial images.  This generally included stringing kites together in series, or by using a combination of kites and balloons.  Interestingly enough it is from KAP, where to this day, George R. Lawrence is credited with capturing some of the largest aerial photos to date.  Lawrence’s technique in fact used multiple kites strung together in combination with a large format camera.  Lawrence’s photos are so large in that he designed a curved plate to provide a larger panoramic view of San Francisco.  It is appropriate that the photos were large as a matter of necessity, the cause being a large fire and earthquake that had devastated San Francisco in 1906.  Although there were many others using kites to capture aerial photography, the methods were generally all about the same.  The largest differences lie in the way in which the photographer was able to capture the image.  As was previously stated cameras were bulky, heavy pieces of equipment.  Therefore the photographer had to either create a kite large and stable enough to effectuate good photography or as is the case today, camera technology had to improve.  From a historical perspective, the history of KAP has yet to find an ending.  Still to this day amateurs and enthusiast alike still attach cameras to kites in an effort to produce beautiful aerial photographs.  As a general rule and because of its limitations, it is no longer a practical method for capturing aerial imagery.  KAP shows us that anything is possible, and provides a small form method for capturing aerial imagery.

Pigeon Cameras

As technology improved, cameras became smaller. This allowed for the use of smaller aerial platforms. It no longer becomes necessary to airlift a camera in a balloon or on a kite.  One innovation that has no other place than its own is pigeon photography. “In 1903, Julius Neubranner, [a] photography enthusiast, designed and patented a breast-mounted aerial camera for carrier pigeons. Weighing only 70 grams the camera took automatic exposures at 30-second intervals along the flight line flown by a pigeon” (History of Remote Sensing, Aerial Photography). In 1909 Neubranner had the opportunity to showcase his fleet of pigeons at the Dresden International Photographic Exhibition.  To most the photos proved a novelty and were used as postcards.  Even though the pigeons were not always reliable in their flight paths, it is of importance to note that there needed to be a time interval.  This is true for a simple reason; physics.  In flight it is crucial to know your time, speed and distance.  If you have two of the three you can figure out the third part of the equation.  For example: if you have a speed of 30 knots with a distance of 10 nautical miles you can determine the amount of time it would take you to travel 10 nautical miles at a speed of 30 knots.  For purposes of reference, the answer is that it costs you about 20 minutes of your time.  When the speed is known it is easier to calculate how many images should be acquired over a certain distance in order to get a complete picture.  Although more of a novelty and like kite aerial photography, pigeon photography goes to show that almost any airborne item can serve as a platform.

Fixed Wing Platforms

As technology evolved so did the platforms used to capture aerial images.  Balloons had been around since the late 1700’s and man had been trying to achieve flight for many years before a successful attempt was made.  The first winged flight was not actually an airplane but a glider designed by a German named Otto Lilienthal. Before the Wright brothers invention of the airplane there had been many different attempts at producing other incarnations of vehicles that were heavier than air.  There were even a few successful attempts that almost made it before the Wright brothers.  It is for this reason that the Wright brothers are also credited with many firsts.  Among the many firsts that the Wright brothers can claim include the first aviation fatality, the first aerial recording and a host of other accidental firsts.  Another first that still exists to this day is the way airplanes are sold.  In order to buy an airplane the salesman will put the airplane on display and a prospective buyer can ask for the opportunity to demo the airplane.  It is in this fashion that “on April 24, 1909, Wilbur Wright was giving exhibition flights in Italy, and on one of these flights he carried a passenger who took motion pictures of the military field at Centocelli, near Rome” (Manual of Aerial Survey).  
If there was ever a place or a time where aerial photography would flourish, it would be WW I.  In the history of aviation, aircraft made it easier and faster to trespass into enemy territory and leave quickly.  The chief of the German General Staff, General Werner von Fritsch, once stated, “The nation with the best photoreconnaissance will win the war” (History of Remote Sensing, Aerial Photography). Having an aerial presence, made it easier to gather information and to relay it back to the command post.  Reconnaissance missions usually required an observer and a pilot. Most commonly if an observer were to relay messages, the observer would use a variety of methods.  Some of these methods included hand signals, message drops, or sketches.  It quickly became apparent that by using a camera the observer would have more accurate information.  This proved to be a very efficient way to gather information and soon it became a common practice. “By the end of WW I, Camera technology had flourished.  “The quality of cameras had improved so much by the end of the war that photographs taken at 15,000 feet (4,572 meters) could be blown up to show footprints in the mud” (Century of Flight; Aviation During World War One).

By WW II, Germany was the most prolific user of aerial photography.  Its use was so abundant that it was used for damage assessment, and mapping.  In fact, some speculate that one reason Germany lost the war is because they stopped using aerial photography.  Use of aerial photography was also important to the Allied forces. In 1945, Admiral J. F. Turner, Commander of American Amphibious Forces in the Pacific, stated that, “Photographic reconnaissance has been our main source of intelligence in the Pacific. Its importance cannot be overemphasized.” 

It was in WW II in which mapping became an important part of America.  It is because of these wars that remote sensing and aerial mapping technology developed so rapidly.

Conclusion

Man has always wanted to be free from the bonds of earth.  Man has always wanted to record his surroundings.  It is in these aspects that aerial surveillance comes to fruition.  Without these freedoms we can neither record nor visualize what we need to know.  It has been a valuable resource to those who use it, and continues to be of value today.  Even though mainly in the past it has been a resource mostly available to military planners, the technology has and will continue to spill over into the civil sector.  This is important because there are many useful aspects to aerial surveillance and many different ways to record the information.  It is from this that we are able to gain the big picture in order to more accurately define the boundaries of our world.  It is in fact, with these methods that the boundaries grow ever smaller.  It is in this way that man frees himself from the bonds of the earth, and it is in this way that man records what he has just freed himself from.