Last week on Knights of the Air, we introduced you to the 1910s version of Google Earth. This involved sending balloons, blimps, and more "experimental" aircraft loaded with as many old-timey cameras as possible over the battlefield.
When those airships returned from the front and landed safely in friendly territory, a slew of army technicians would develop the images inside their makeshift darkrooms (located in the back of tents, inside sequestered homes, or just out in the middle of poorly constructed cabins).
Once developed, the photos were then cut up and stitched together with pins and glue to create sprawling aerial maps of the battlefield that would be used to track enemy movement and chokepoints in the terrain. In the days when owning an aircraft was like owning a Ferrari, the military used their flying machines as much as possible to gain whatever advantage they could.
For those of you used to using Photoshop, check out these photos to see how it was done in the old old school.
In a busy German field lab, a photo technician (seated) uses an electric hair dryer to dry glass negatives developed in the darkroom at the left
With individual exposures pinned into place on his worktable, a British photo-technician creates a composite map.