The history behind the current flat light gray paint schemes came from research conducted into reducing the visual signature of military aircraft. Aviation artist Keith Ferris spent a few years trying to convince the USAF that their planned blue scheme for the F-15A was misguided.
He rightly observed that what looks intuitive for someone seeing an aircraft parked on the ground, and looking at the sky, does not translate when actually in the air looking for another aircraft.
In fact, the darker the color, the easier it is to see it. So, based upon Ferris's good inputs, a series of visual acuity tests were performed on aircraft with various paint schemes.
The "air superiority blue" of the original F-15A did not perform as well as the flat light gray, which did the best. Ferris precisely predicted the results. As an aviation artist, he spent a lifetime learning how to realistically paint aircraft in flight. So, he had a detailed insight into how colors and light works in the air.
In my own flying, the furtherest away I ever saw another aircraft while flying my own airplane was a single T-38 painted in that black sheme at UPT. I saw it ten miles away immediately. Had it been painted the glossy white, I would not have seen it that far away unless I was lucky and had a perfect background for it stand against.
The AF went a step further and experimented with shining high intensity strobe lights on the aircraft surface. By significantly reducing the natural dark shadows, the AF found that aircraft could sneak up on a ground target without being seen until extremely close, even if you had a group of people standing looking at the right location and knowing an aircraft was inbound to their location.
For years, C-130's were painted in the NATO green camo scheme. It looks like it makes sense to avoid air-to-ground observations. Under the right conditions it can. But, against a light ground scheme, it stands out. During Vietnam, the MC-130E's were painted in a flat black scheme and it worked brilliantly at night. Ground crew sometimes walked into the plane while it sat in the tarmac -- that's how well in blended in with the night sky!
But for one scheme, for all conditions day and night, flat light gray works best. You want the surface of the aircraft to blend in with a highlighted sky or a typical hazy summer groundscape. At night, it works nearly as well as the Vietnam era flat black scheme.
In World War II, keeping the aircraft polished could provide a small increase in speed. However, more the point the USN believed blue blended better with the ocean. In reality, it made our aircraft easier to see for Japanese fighters. The bare aluminum scheme adopted later by the USAAF worked better unless the sun glint off the polished surface shined toward the enemy. Then that glint could give away the location twenty or more miles away! But a dirty little secret is that the USAAF brass WANTED the Luftwaffe fighters to find the bombers. In this way, they used the bombers as bait so their own gunners and the USAAF fighter escort could butcher the Luftwaffe's fighter arm. And it worked spectacularly well!
However, most often our bombers were on German radar and they vectored the Luftwaffe to them anyway. But the flat brown made the aircraft stand out against the sky even worse than the bare aluminum skin did. Unfortunately, during that war and subsequent ones, no one realized what it took detailed flight tests to discover. And all those tests were the result of one aviation artist named Keith Ferris!
Cheers,
Ken
