Their work mainly had to do with deceptive coloring. Another approach was more architectural. That was used to disguise large areas.
For example, above are reconnaissance photos taken of Hamburg, Germany during World War 2. They show that the downtown end of Alster Lake was covered so as to suggest the city center was farther east than it actually was. The nearby harbor industrial area was more difficult to disguise in this manner. As it happened, much of the city was later wiped out by massive Royal Air Force raids.
The main subject of today's post is camouflage of American aircraft factories on the West Coast. At the time of World War 2, much of US aircraft industry was out of range from enemy attack. The exceptions were vital facilities close to the Pacific Ocean, and within reach of potential Japanese attackers launched from aircraft carriers.
The form of camouflage selected in the weeks following the Pearl Harbor attack was making the factories appear to be innocent neighborhoods. These neighborhoods were clearly fake when viewed at close range. But that was thought to be good enough, because attackers in the heat of combat were under psychological strain while having little time for contemplating a target area. That is, the hope was that attackers' bombs would be poorly aimed, missing many vital areas.
We now know that the Imperial Japanese Navy was essentially incapable of attacking the West Coast using aircraft carriers at the start of the war. And after most of their large fleet carriers were destroyed at Midway in June 1942, such attacks were military impossible other than as suicide missions.
Nevertheless, those camouflage neighborhoods remained in place until after the war ended. I remember seeing the Boeing factory camouflage when I was a young boy.
Below are photos of major West Coast camouflage projects. The ones in California were more successful than the one in Seattle because their neighboring topography and settlement patterns were much easier to blend into.