What I am wondering is if there are big differences in spectrums between these two kinds of orthochromatic films, aerographic and medical.
(as for developers, I typically use metol variants D23-like, sometimes two baths à la Beutler, and otherwise have some of the usual raw chemicals to mix whatever)[/QUOTE]
The HRU green xray film is designed for use with a specific phosphor that is used, which has specific very narrow bands of green lines that it must have best sensitivity to, which a general purpose ortho film does not. I woulld think think the green xray film spectral sensitivity is different, but now much so would be only a guess. I would guess the green xray has better green sensitivity than other ortho films. Looking at a brite light through unprocessed HRU it appears to be very magenta in color, which is likely the ortho sensitizer.
I'm surprised that there are orthochromatic aerial films. I had a K20 US aerial camera that used 5 1/2 inch wide roll film, but never say any US ortho film stocks for that. Just as ortho films are 4-8 times more sensitive than color blind emulsions, pan films are also much more sensitive than even ortho. In aerial photography, where focus is mostly at infinity was fairly large aperatures and fast shutter speeds, that film speed is pretty important.
I currently use 8x10 HRU cut down to 4x5 processed in D23 at 1:7 dilution for 20 minutes. I'm able to get a good density range of about 1.8 with that processing. I do not remove one side, since that would cause other issues, but process 12 sheets at a time in a Doran cut film tank. I use a yellow filter to reduce the amount of light that reflect back off the second film surface, which acts like a halation layer due to its reflectivity. I also shoot some ortho litho films as well, using red construction paper behind the thin ortho litho film to take up space and help anti-halation while being easy to see under red safelight. To ortho litho, red is black, or at least dark grey.
Have fun,
Alan Townsend
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