Drew - aerial photography has certain advantages that films at sea level don't have, especially in terms of shadows and exposure scale - on the other hand, they need to cut through haze and image tiny objects at huge distance - which is why people get in such a tangle with the repurposed Agfa films.
From Bob's book, the persistence of triacetate in LF film bases was because of the need to enable pre-photoshop compositing methods using solvents and emulsion stripping.
It's just the opposite, Interneg! Triacetate is not dimensionally stable. Ever try to order a pin register bar for an extant punch? You submit your punched sample either on mylar (Estar) or brass shim stock, or they send it back. As far as acetate sheet film base, that was just an interlude for Kodak starting after Ektachrome 64 up till E100G. Fuji adopted the superior polyester base late with Astia 100F and Velvia 100F only. Almost all b&w sheet films were on polyester base all along, at least in modern decades. Acetate is hell to maintain register with mechanically. Other advantages of Estar is that it's stiffer and sags less in a holder, and is more robust in automated development.
Drew - I know how dimensional wonky triacetate is - put a sheet of 4x5 on even a seemingly cool light table & watch it curl! Fastest way to tell whether the base is estar or not. What I was pointing out is that on the available documentary evidence, Kodak made no sheet transparency films on estar in 1988 (but all sheet colour and BW neg, lab films, separation films etc were on estar), & then according to Bob Shanebrook's account phased them in over the next decade as computers displaced traditional compositing methods, finally allowing for a more dimensionally stable product to be made. When making dye transfer seps, you should not need to expose the camera neg to heat shifts sufficient to cause registration to wander.
The same 1988 product coating list in Bob's book recounts no fewer than 35 aerial film SO- materials - some of which were in the resolution range of ADOX's CMS 20.
Yes...Originally Posted by interneg
In particular Aerecon High Altitude, ISO 16, 630 l/mm at TOC 1000:1 contrast, but amazingly 320 l/mm at TOC 1.6:1 low contrast. ...and possibly not all films were disclosed.
Aerial duplicating film may reach 800/250 l/mm depending on contrast.
CMS 20 may reach 800lp/mm (1600 l/m), catalog says, but this is document Microfilm, probably less suitable than AHA or TP for Recon.
https://www.kodak.com/uploadedFiles/...up/EN_as57.pdf
The 1414 emulsion for example was coated in 0.001" thick film,it was used in 30 miles long camera rolls, a lot of shooting. Some rolls contained different kinds of film (Shanebrook's ).
Last edited by Pere Casals; 18-May-2020 at 13:56. Reason: Rectified lp/mm by l/mm
I can't get into Kodak's too-many-tentacled head at the time, and it would be up to insiders to tell the story. But Fuji has stuck mainly with triacetate to this day, and what modern scanners and digital post-correction has allowed is extremely rapid workflow where dimensional stability is less an issue. There must be some other reason, perhaps reducing the variety of overall substrates required for both b&w and color sheet films. In the interim, Fuji tended to dominate the color chrome business, and their films got scanned just as much, various ways. So I don't quite see the relation. Having around over a decade's worth of 8x10 chromes on miserable acetate, I went through one heck of a lot of nitpicky dust-free masking and remastering of some of those during our relatively few months of stable humidity onto polyester master duplicates like Astia 100F. Now some of those have become third generation Provia contact internegs for sake of RA4 printing. But the color quality is better than ever, and even fine detail has held up well. A ton of work, but nobody is going to mistake those for inkjets!
Pere - most modern recon filming was on true color, not b&w, and certainly not something like Tech Pan or microfilm. The whole point is something which can be intuitively analyzed. Drones and satellites are more convenient for infrared, UV, false color etc. I know there are very sophisticated hybrid modes in use, but how soon all that began is probably highly classified.
More than true color, false color. Camouflage detection film extents Red channel sensitivity to IR, so vegetation is displayed pinky and camouflage is seen original, you know were tanks and guns are.
But modern uniforms and camouflages reflect IR like vegetation, it looks, so spectral camouflage detection it's not useful anymore, now they are located by whatsapp traffic
Compare color of uniform at left and right:
Soldiers at left have the cap/beret in tmx underfixed pinky, but soldier at left/front wears a detectable camouflage.
https://www.guns.com/news/2013/06/08...he-congo-video
Kodak Aerochrome contributed to detect military assets in the WWII, but I guess that at some point somebody realized that those tanks camoufled with natural vegetation were not bombed... while those under fabric camouflage were soon destroyed.
Color, or false color, was used for that until this was discovered by rivals, and used to divert bombings to empty places. Instead high altitude Aerial recon to detect strategic infraestructures/activity/ships would have required BW, the 320 lp/mm AHA film delivers at 1.6:1 contrast were an asset, satelital glass could resolve 400lp/mm for sure.
Well, you did ask for an opinion. Here's mine. In LF, it just doesn't matter. That's one of the major reasons to move up to LF.
One of the things you get by moving to LF is the considerably smaller enlargement ratio between film size and print size. Which more or less renders resolution differences between films moot. Not that you'll ever be limited by the resolution of a film in the first place. But that's not what you asked.
Bruce Watson
Pere - you're speculating as usual. But being a large format forum, it's not THAT large ... I'm not planning on backpacking with some exotic camera that weighs half a ton anytime soon. Something with a familiar Kodak or Fuji or Ilford product label on the box is plenty good enough for my purposes.
As usual no speculation, one thing was funny orthoimagery at 8000ft and another thing was serious military recon from high altitude or from orbit, in those situations you don't want a color film sporting 40lp/mm, but a BW taking 300 to 600 lp/mm depending on contrast. If you still want color then you take 3 or 4 BW images with different color filters.
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