Paul Parson brings up a good point with regard to the color sensitivities of film and, indirectly, the question of which film stock was used in the newly found aerial photos. Such information is important for just the reason he stated.
I do not know Paul's background in photography but I would argue these films are panchromatic and it is not my intent to step on anyone's toes -I never learned to dance- but there are couple of things I think are worth noting and clarifying.
Even within orthochromatic films of one company there were different sensitivities manufactured, while, generally speaking, the difference in the spectral sensitivities of panchromatic films might only be seen when looking at the emulsions produced by different companies, e.g. Kodak vs. Agfa vs Ilford.
I am guessing here but I think the film used in these particular aerials photos was a panchromatic stock. Some of my reasoning for this is: 1) Ortho films have substantially more emulsion contrast than pan films - these images appear to be from a lower contrast film; 2) the many tonal values in the sky and clouds would be almost non-existent if reproduced by an ortho film unless a filter (K-2 or eqiv.) were used, but that would be counterproductive for aerial photography since a K-2 requires a full stop increase in exposure for a film that was likely no faster than 25 ASA, and, if you are photographing islands then there is little need to reproduce the sky correctly; 3) pan films were developed well before 1920 and in wide use by 1930; 4) after looking at color images of the island flora from several sources, the grey tones reproduced in the aerial films seem typical of pan films I have experience with.
With regard to Gloria's question: Yes, ortho films are insensitive to portions of the red spectrum but no, they will not reproduce a red light as a dark area. If a light is not bright enough or within the range of the film's spectral sensitivity it will not register at all but that is different than registering darker. I believe Paul was referencing light reflected by an object as opposed to an object being the source of light.
Also, while I know absolutely nothing of the flare that may have been on AE's last flight --its composition, it's manufacturing, or even its proper use -- I would be more than surprised to find that it would have emitted such a severely limted range of the spectral light that it would not register a density even on an ortho film. Perhaps someone here can detail the material used in the flare and the resultant spectral wavelength throughout its ignition.
And Ric, if you made it this far, will you be releasing any more of the low-res copies of these prints? And what thought has been given to the release of the digital copies of the films once you and Jeff have returned from NZ? I'm not trying to stir the pot here, I know this is all under TIGHAR's purview, I'm just hoping to know an answer to the disappearance of AE and FN before I slide underground. I think these photos and a return to Niku to further explore the anomaly are the best chance of this happening, distracting lawsuits aside.
cheers,
d
Now is the time for all good men.
Pogo