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 Post subject: You want dynamic range?
PostPosted: Wed Jul 02, 2008 11:37 am 
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I just learned that panatomic x (which I now have a 2000ft 5" roll of) and POTA developer can achieve 20+ stops of range :shock: 8)

This is going to be perfect for some projects I've had on the shelf.

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PostPosted: Wed Jul 02, 2008 3:41 pm 
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That sounds impressive. If my metal arithmetic is correct, I would need to combine 5 exposures at -4, -2, 0, +2 and +4 ev to achieve something similar with the D300, assuming it has roughly a 12-stop dynamic range.

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PostPosted: Wed Jul 02, 2008 3:46 pm 
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POTA = Pain (of?) the ass?

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PostPosted: Wed Jul 02, 2008 7:10 pm 
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Keithwms wrote:
I just learned that panatomic x (which I now have a 2000ft 5" roll of) and POTA developer can achieve 20+ stops of range :shock: 8)

This is going to be perfect for some projects I've had on the shelf.


I am a bit surprised to hear about the dynamic range. When I was in college we had Royal-X Pan, Tri-X Pan, Plus-X pan, and Panatomic X.

No one I knew used Royal-X as pushed Tri-X gave better results in most cases.

Tri-X had the most range. ASA 400

Plus-X had more contrast and less range. ASA 125 (I believe)

Panatomic-X behaved like slide film. ASA 32 (Also a vague memory) Your exposures had to be dead on and the contrast was high. You could over-develop it and make it behave almost as litho-film.

I guess it is not your father's Panatomic-X film.

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PostPosted: Wed Jul 02, 2008 11:37 pm 
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Challenge number 1 is finding a scene that is 20 stops. Probably a scene that includes both the sun and the interior of a cave.

Challenge number 2 is finding a meter that can accurately confirm that for you.

Challenge number 3 is finding a development method to actually preserve detail over that range.

Look into some of Bruce Barnbaum's stuff. He uses highly dilute HC110 with standing development to get 15+ stop scenes into a printable range on film. I'm not sure which kind of film he uses, but I think it's something modern.

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PostPosted: Thu Jul 03, 2008 12:20 am 
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Paul, I have the perfect application for this and I will be using every last one of those ~20 stops. Stay tuned. Oh and I don't need to meter, I will develop by inspection... of polaroid 665! 8) And I will be shooting to 5" roll film on which I can do strip tests.

Okay I'll give you a hint, panatomic x and POTA were the combination used to film atomic bomb tests....

POTA is also just about the only type of developer that can get any range out of tech pan.

P.S. This actually is your father's panatomic x that I am talking about. It's actually an amazing film. I have the good old stuff and also some fresh stuff with extended red sensitivity (the aerial recon version). I've got about 3000 shots of fresh panatomic x now; I sold off all my 8x10 polaroid to afford it.

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PostPosted: Thu Jul 03, 2008 12:38 am 
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Keithwms wrote:
Paul, I have the perfect application for this and I will be using every last one of those ~20 stops.

...

Okay I'll give you a hint, panatomic x and POTA were the combination used to film atomic bomb tests....


Should I be calling the US dept. of homeland security here?

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PostPosted: Thu Jul 03, 2008 12:45 am 
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Well I don't the think the DHS would listen to a Canadian. But the mounties might.

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PostPosted: Thu Jul 03, 2008 10:10 pm 
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Keithwms wrote:
POTA is also just about the only type of developer that can get any range out of tech pan.
Why would you want a lot of range out of tech pan? I mean its whole calling card is that its contrast (and therefore actuance) is so great that with its tiny grain size it has huge resolution. If you tame the contrast in order to get a wider range, you lose that actuance. I guess the main application would be huge enlargements from small film to keep the grain size down, but you wouldn't be getting the most out of it.

Along similar lines, however, I just stopped by Peace Camera in Raleigh today (I've started working at Duke so I'm a lot closer now). They have a lot of rare films there. I picked up a roll of PL25, which should be interesting. I also bought a box of 25 4x5 sheets of Maco 820 Aura IR film, which is the version without the antihalation layer. It only cost $30.

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PostPosted: Thu Jul 03, 2008 10:53 pm 
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drpablo wrote:
Why would you want a lot of range out of tech pan?


I wouldn't, but if you did, that's how you get it. For me, it's panatomic x all the way, I love the stuff. Just for fun I shot a candle in the dark with it. Just with pyro developer, I think I got enough range for a passable shot, but I'll be able to get twice as much with the POTA.

Image

For some reason I toned this scan in PS. Anyway, the range I measured for this scene was ~14 stops. So I hit it with wd2d+ and underdeveloped a minute or so. I figure I dug out 10-12 stops with no real effort. Actually there is some tonal structure in the flame, but since it was a long (2 sec) exposure, it's mostly motion-blurred out.

drpablo wrote:
Along similar lines, however, I just stopped by Peace Camera in Raleigh today (I've started working at Duke so I'm a lot closer now). They have a lot of rare films there. I picked up a roll of PL25, which should be interesting. I also bought a box of 25 4x5 sheets of Maco 820 Aura IR film, which is the version without the antihalation layer. It only cost $30.


You mean Efke PL25? Didn't know it came in rolls. I have a few boxes of PL25M minisheets that I shoot on the rb, they are very nice in wd2d+. Not nearly as fragile as some allege. Anyway wd2d+ apparently has some protective, hardening properties.

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PostPosted: Thu Jul 03, 2008 11:45 pm 
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Wow, sweet, maco aura is something I wish I could get my hands on. Also, your test looks pretty impressive, Keith.

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PostPosted: Fri Jul 04, 2008 12:09 am 
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Walter, I might be wrong, but I think you can just take the regular IR film and wash the AH dye off the backside with water. I recently started doing water presoaks before using pyro, and noticed that the presoak water was washign something off. So I did it with lights on and it came off the back side of the film. I think it must be AH coating. My suggested experiment is to wipe the backside of some IR film with a damp paper towel and see if something comes off and if that area then halates.

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PostPosted: Fri Jul 04, 2008 12:33 am 
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Keithwms wrote:
Walter, I might be wrong, but I think you can just take the regular IR film and wash the AH dye off the backside with water. I recently started doing water presoaks before using pyro, and noticed that the presoak water was washign something off. So I did it with lights on and it came off the back side of the film. I think it must be AH coating. My suggested experiment is to wipe the backside of some IR film with a damp paper towel and see if something comes off and if that area then halates.


Yeah, I think you (or someone else?) has suggested that before. The only thing that holds me back is the annoyance of finding a way to dry it without streaking it. I guess you could just try to rub it off with a damp cloth like you suggest, but I think for best results you'd probably have to soak it and then dry it properly - kind of a pain in total darkness.

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PostPosted: Fri Jul 04, 2008 12:43 am 
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walter23 wrote:
Wow, sweet, maco aura is something I wish I could get my hands on.
They had one more box of 4x5 there. Give them a call at (919) 836-2222 to see if they'll ship it to you. It cost me $30 for the box of 25 sheets.

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PostPosted: Fri Jul 04, 2008 11:15 am 
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Paul can you shoot 2.25 x 3.25" minisheets on your hassie? If so I would recommend trying this, I see several benefits. Fortunately there are quite a few minisheet holders for the rb on the market, I bought a half dozen. Anyway for pyro stuff the results are amazing, I shoot two sheets and tray develop one, decide whether to raise or lower contrast, then tray the next.... One thing about the PL25M, I really think that anything meaningful should be shot a few times, you will want backup negs. That material does have spurious issues in my experience.

Oh another thing, a friend introduced me to the fomas, 100 and 200, that stuff is very nice for the price. Again responds well to pyro.

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PostPosted: Fri Jul 04, 2008 12:59 pm 
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Keithwms wrote:
Paul can you shoot 2.25 x 3.25" minisheets on your hassie?
No idea, I've never looked into it. It would entail getting a back that could accomodate it.

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One thing about the PL25M, I really think that anything meaningful should be shot a few times, you will want backup negs. That material does have spurious issues in my experience.
I just bought one roll to see what it's like. I rarely use my slow stuff like Tech Pan (still have about 9 rolls of 120 and 45 sheets of 4x5).

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Oh another thing, a friend introduced me to the fomas, 100 and 200, that stuff is very nice for the price. Again responds well to pyro.
Cool, the 200 would be good, esp if I can push it.

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PostPosted: Fri Jul 04, 2008 1:03 pm 
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Paul,

Look here: http://www.clubhasselblad.com/hasselbla ... ilm-holder

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PostPosted: Fri Jul 04, 2008 2:08 pm 
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Incidentally, I think the foma may be the same as the arista.edu, but you'll have to check that. In any case both are super and quite forgiving.

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PostPosted: Sat Jul 05, 2008 10:10 am 
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Keithwms wrote:
Okay I'll give you a hint, panatomic x and POTA were the combination used to film atomic bomb tests....


But weren't these heavily solarized during the real nuclear flash? Do you count the negative image (well, positive on the negative...) as additional exposure range, then? At least the olf films I have seen all were solarized - about the only film I ever saw, that actually wans't a pseudo-solarization during printing.

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PostPosted: Sun Jul 06, 2008 10:38 am 
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Efke 25 in rolls is R25, I have 2 bricks in the freezer, I find R100 to be a better film overall, the 25 tends to over contrast easily.

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PostPosted: Wed Jul 09, 2008 3:49 pm 
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René_P wrote:
Keithwms wrote:
Okay I'll give you a hint, panatomic x and POTA were the combination used to film atomic bomb tests....


But weren't these heavily solarized during the real nuclear flash? Do you count the negative image (well, positive on the negative...) as additional exposure range, then? At least the olf films I have seen all were solarized - about the only film I ever saw, that actually wans't a pseudo-solarization during printing.

René


I don't know for sure, but I don't think they were necessarily solarized, they were able to get very short exposures with the rapatronic cameras. I think the "shutter" speeds were of order nanoseconds.

What is the exposure for a direct sun shot? I dunno, at ISO 25 and f/16 maybe a microsecond or so, just a guess. And with POTA the film loses 3 or 4 stops of speed, so the ISO would have been 2-4 or so. So I am thinking that an exposure without solarization is possible. I could be wrong.

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PostPosted: Wed Jul 09, 2008 5:15 pm 
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Packard wrote:
Keithwms wrote:
I just learned that panatomic x (which I now have a 2000ft 5" roll of) and POTA developer can achieve 20+ stops of range :shock: 8)

This is going to be perfect for some projects I've had on the shelf.


I am a bit surprised to hear about the dynamic range. When I was in college we had Royal-X Pan, Tri-X Pan, Plus-X pan, and Panatomic X.

No one I knew used Royal-X as pushed Tri-X gave better results in most cases.

Tri-X had the most range. ASA 400

Plus-X had more contrast and less range. ASA 125 (I believe)

Panatomic-X behaved like slide film. ASA 32 (Also a vague memory) Your exposures had to be dead on and the contrast was high. You could over-develop it and make it behave almost as litho-film.

I guess it is not your father's Panatomic-X film.


I thought Panatomic was ASA 25 ... maybe 32 ... ... maybe 25 was that Kodak slide film.

The stuff you got your hands on is the aerial film ... wow ... should be extremely fine grain ... whatcha got planned ???

Gary

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PostPosted: Wed Jul 09, 2008 5:18 pm 
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Keithwms wrote:
René_P wrote:
Keithwms wrote:
Okay I'll give you a hint, panatomic x and POTA were the combination used to film atomic bomb tests....


But weren't these heavily solarized during the real nuclear flash? Do you count the negative image (well, positive on the negative...) as additional exposure range, then? At least the olf films I have seen all were solarized - about the only film I ever saw, that actually wans't a pseudo-solarization during printing.

René


I don't know for sure, but I don't think they were necessarily solarized, they were able to get very short exposures with the rapatronic cameras. I think the "shutter" speeds were of order nanoseconds.

What is the exposure for a direct sun shot? I dunno, at ISO 25 and f/16 maybe a microsecond or so, just a guess. And with POTA the film loses 3 or 4 stops of speed, so the ISO would have been 2-4 or so. So I am thinking that an exposure without solarization is possible. I could be wrong.


Sorry, I know, it is neither the most relevant, nor the most beautiful topic, but I read up a bit on the physics of a nuclear explosion. It seems, that even a "small" a-bomb will produce a flash several times as bright as the sun (seen from earth). Furthermore it initially contains a very large amount of UV and Gamma radiation, which would add considerable density, especially to these old films.
Considering that for pics of the sun you would use a ND filter, which lets pass only 1/1000 of the solar light, you would typically achive 1/1000s exposure at 100 ISO. This would equate to 1/250s at 25 ISO or 1/60s at 6 ISO. This is of course very much dependent on the instrument used. Assuming, that the nuclear fire ball reaches 5 times the brightness of the sun (I haven't found robust data on that, during my quick search), you would reach 1/2000s at 6 ISO - but still with the 1/1000 ND-filter. The film snippets I have seen clearly were not made with such a dense filter on the camera, as you couldn't film anything through it except for the brightest flash. But this is ony guesswork, at best. Taking into account the massive fogging (I would assume, it has the same effect as pre-fogging to achieve better low-light response?), I can easily imagine the solarizing effect. But apart from those short film scenes, where I clearly have seen the solarization, there might be much more material, which isn't.
I better stop here…

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René

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PostPosted: Wed Jul 09, 2008 6:02 pm 
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A 1/1000 ND filter ... would that be a 1/3" steel plate or maybe a 1/4" steel plate?

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PostPosted: Wed Jul 09, 2008 8:32 pm 
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Well, I am not saying that they were or weren't solarized or partly solarized, I just don't know. I am just saying that nanosecond exposures were possible with the rapatronics, so... it's possible that nonsolarized photos were achieved, and ~20 stops of range have been seen with POTA.

I see your comment about the initial gamma burst, but I am not sure offhand what the response of film will be to that. I do recall reading that a photographer who went to Chernobyl right after the accident had most of his film fogged pretty badly but he did manage to salvage a few snaps.

My guess is that for atomic bomb tests they put a lot of cameras behind a lot of lead and shot through some pretty thick glass from a long way away. The film itself can be behind the lead, only the lens needs to poke out, and the opening in the lead need only be as large as the aperture. Hell, the aperture itself could be made of lead 8) So, with a typical long lens, the opening would be a few millimeters, and thus the direct gamma burst would only hit a small central part of the film, while the image circle would be much larger than the aperture.... At least, that's what I'd try to do if I didn't want to have too much rad damage to my film.

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