Even "back in the day", they had infrared film, a precursor to multispectral or hyperspectral, so the netting scheme wouldn't work. But the caveat
is they couldn't detect the camo in real time until they had IR imaging rather than just film.
The problem with analysis of this photograph is the quality is too poor to really draw conclusions. I learn towards bunk, but could be persuaded
otherwise if the original film were presented as a tif with higher resolution.
The post about black and white film not having equal response to all colors is true as well. Kodak made "technical pan" film that titled towards
The opposite of technical pan was Kodak orthochromatic. This film was not sensitive to red. But in the "modern era", most black and white film was
Tri-x and then later Tmax.
Since the photo is old, I'm going to guess Tri-X was used. It has a decent spectral response. It goes well into the UV, but not into IR at all.
So if Sandia was playing any tricks, it would be in the UV spectrum. Perhaps the netting had a phosphor that glowed in UV when exposed to sunlight.
Most photographers use a "sky/UV" filter to get rid of UV light since atmospheric haze is proportional to the inverse 4th power of the wavelength.
[Translation: filter UV and you get rid of a lot of haze. I use a research grade 400nm filter when I shoot Groom Lake from Tikaboo to get clearer
shots.] But it is possible whomever took the shot didn't have a UV filter, plus the cheap UV filters you get from the camera store don't really
filter much UV.
Note that digital cameras have the opposite response. They are poor at UV and sensitive to IR. Of course, the photographers still use a sky/uv filter,
but mostly out of habit.
Speaking of camo and Tom-foolery, Kim Dotcom had an inflatable T72 tank, but that didn't fool the authorities.
OK, the tank came after his arrest, but the story is more entertaining the other way around.