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FilmIs4Ever
07-11-2008, 02:21 AM
Unfortunately film and audio are two completely different things. Tubes aside for a moment, tape is child's play in comparison to coating film. So this is an imperfect analogy at best.

Photo Engineer
07-11-2008, 08:05 AM
Ummm, Kodak quit making professional audio and video tape due to poor quality. Other products were superior. The Kodak products were good enough and inexpensive enough for only the amateurs not the pros.

PE

David A. Goldfarb
07-11-2008, 09:51 AM
They seem to have put out a quality CD-R, though. I've had fewer problems with Kodak Preservation Disk CD-R media than with other CD-Rs, but they're also more expensive and not widely available, so I don't know how well they've done in the market.

Photo Engineer
07-11-2008, 10:14 AM
They made a determined effort to put out a quality CD and DVD material that has very good keeping. One of the guys who ended up working on this project used to work for me.

PE

thuggins
07-11-2008, 11:12 AM
Internally there are voltages around 350 to 700 volts, so fiddling is done with a great deal of caution. (Voltages that can kill you, or at least make a pretty good mess of your underwear)



Actually, voltage can't kill you. That's why you can grab the spark plug wires of your car and get 20000 volts, or more than 1 million volts from a Van Der Graff generator, without any harm. It's the amperage that kills you, voltage only hertz. :-)

Photo Engineer
07-11-2008, 11:23 AM
Van DeGraff is more like 100 - 200,000 on average. The Tesla coil puts out 1 - 2 M on average. They used to demonstrate them both at the old Buehl Planetarium in Pittsburgh along with the science behind them.

However, for a person with heart problems, any sufficient spark or electrical jolt can kill.

The high voltage from the tube TV flyback transformer can leave a hefty voltage in the tube itself which is a super sized capacitor that can have lethal results if discharged through the body. And, that is another point. The path through the body is critical. A jolt across two fingers on the same hand is less lethal (generally) than across 2 fingers of both hands. Also, DC is more lethal than AC due to the "kick" of the AC and the "stickiness" of the DC.

PE

ic-racer
07-11-2008, 01:45 PM
Actually, voltage can't kill you. That's why you can grab the spark plug wires of your car and get 20000 volts, or more than 1 million volts from a Van Der Graff generator, without any harm. It's the amperage that kills you, voltage only hertz. :-)

Usually, but in the case of commotio cordis only a few milliamps are involved.

Also, the minimal current to fibrillate the human ventricle is a few milliamps (when applied to the endocardium on the peak of the 'T').

Paul Goutiere
07-11-2008, 06:43 PM
Actually, voltage can't kill you. That's why you can grab the spark plug wires of your car and get 20000 volts, or more than 1 million volts from a Van Der Graff generator, without any harm. It's the amperage that kills you, voltage only hertz. :-)

Voltages available on the plates of a tube amplifier can and have stopped peoples hearts. Serious injuries caused by the bodies reaction to a shock are also possible. The VA available in a tube amplifier are quite enough to do a person harm, because there is quite a bit of current involved as well.

So yes, it will be the amperage that will do harm. I suggest this site:

http://www.dansdata.com/gz013.htm

And here as well:

http://www.bassengineering.com/E_Effect.htm

ic-racer
07-11-2008, 06:48 PM
Boy, is my last post way off topic.

Anyway, back to the point. There was some anxiety on my part surrounding the termination of US tube production back in the 80s. Not only did I have a lot of money tied up in tube guitar amps, the sound was a key element of my playing. If the analogy between the tube and film industries can be made, I don't know, however, I can make an analogy of similar anxiety, as I anticipate potential cease of US film productions. For I have a lot of money tied up in film cameras and darkroom equipment and the silver image is a key element in my art.

(Comments on B&W only)
How good does film need to be?? The 'analog B&W process' is a heavily distorted already. For example all color information is thrown out the window. The image is 2D instead of 3D. The grain gives texture to objects without texture. And in many (not all, but most) cases the density range of the image is compressed. These 'distortions' are what makes the medium so cool! Would I be happy with an inferior product? Perhaps, as it would be 'better than nothing.' (but I wouldn't let any manufacturer know those thoughts ;) )

http://www.apug.org/forums/forum234/48008-minox-anyone.html

Photo Engineer
07-11-2008, 07:36 PM
Ever see I-Max Stereo?

It is possible to eliminate just about every fault with analog photography (or just about) that you mention and the nice thing is that no digital photo system can even approach I-Max for the outstanding quality it produces.

PE

Emulsion
07-12-2008, 06:19 PM
PE,

IMAX 3D is a very impressive cine system. The 65mm negative (15 Perf frame) contains a HUGE amount of information. Another impressive systems is "Showscan".

From what I have read on the Internet it appears that IMAX are moving to digital. Hopefully only for some programming....
http://www.gizmodo.com.au/2008/03/imax_theaters_to_ditch_film_use_digital_dlp_projec tors-2.html

65/70mm 5 perf movies are almost gone now. Despite the new modern small cameras and the fact that the film stock budget is a small % of a feature production, it appears that quality is less of a consideration than other factors.

Emulsion.

Photo Engineer
07-12-2008, 06:27 PM
Yes "Gizmodo, the gadget guide. So much in love with shiny new toys, it's unnatural." So, I wonder how much of this hype is unnatural wishful thinking. After all, how long have we been hearing that digital motion picture projection is "just around the corner". I have seen a theater presentation of the newest Kodak system here in Rochester and was not impressed. It was " ho hum ". In fact, it was, how shall I say it? -- mmmmm- Digital.

PE

PHOTOTONE
07-12-2008, 07:21 PM
The unfortunate thing about theatrical exhibition of movies is this. While 35mm film "can" be superior to digital projection, it seldom is, due to insufficient training and skill of the projector "operator". I won't say projectionist, as that Union position went away long ago in most smaller towns. Back when a projectionist had to have training, film projection was wonderful. Now, with automation, for years it has been barely acceptable. Digital provides better "hands off" image quality in many locations. I know, I used to own theatres.

Back when I was growing up, and working as a projectionist, we used to clean lenses, projectors, lamp houses, etc. on a regular schedule, we never let film hit the floor, or any other thing that would allow it to pick up dirt or dust, and in the best houses one print (one single print) of a film could be run for 6 months and still look brand new. That would be 2 or 3 shows per day for six months. The only venues that have this type of quality nowdays are the I-max and Iwerks type theatres, where the operators are "still" well trained.

PHOTOTONE
07-12-2008, 07:37 PM
One thing that hasn't been mentioned about vacuum tubes is this. Vacuum tubes don't have a shelf-life. Once made, it can sit unused for decades, and be as good as it left the factory, therefore a "run" of a certain tube can be made, and may not have to be made again for 5 or 10 years, depending on demand. Big difference with a dated product like film, that has to be sold within a fixed period of time. You can take a brand new tube from the 1920's, (for example) and use it and it will deliver the same results as it did when it was made. If not used, and not broken, it doesn't age.

Murray@uptowngallery
07-14-2008, 01:50 AM
I have been to an IMAX theatre only only once for a full-length feature, and saw a very short one at Disney World I think.

The full-length feature made me wonder what was so special about it. It was so damn loud I sat in an uncomfortable position covering my ears for a good portion of the movie, and I have never done that in a theatre, except maybe a 3rd row seat at Saving Private Ryan' - I assume it's possible they simply had the volume up too high, and it has nothing to do with the technology. (I avoided 'Earthquake').

However, at the same show, the image looked out of focus or there were at least two different 'projections' (it is projected, right?), that were out of register.

I can't really say what I was seeing but it gave me a headache after a while. Again, this could have been an operator training issue or some other lack of proper procedure. The net effect was that I did not see any advantage in paying more for an IMAX ticket.

AutumnJazz
07-14-2008, 04:17 AM
IMAX uses one projector.

Photo Engineer
07-14-2008, 08:51 AM
Murray;

You were apparently looking at a 3D image witihout the goggles or were having fusion problems with the goggles they gave you due to a bad fit.

PE

Aurum
07-14-2008, 08:58 AM
Wikipedia link (http://en.wikipedia.org/wiki/Imax)

Good photographs of some of the equipment. I could do with a Xenon bulb like that for my enlarger! :D

Don Wallace
07-14-2008, 10:16 AM
Tube amps exhibit a lot of distortion. So technically, solid state is better.

This is an important point and I think it is important to distinguish between audio systems and guitar amplifiers. With the former (and I am not an audiophile, so I could be wrong), you want faithful reproduction of the sound source (whether CD, disk, whatever). On the other hand, guitar amplifiers colour the sound of the original signal and this colouration is an integral part of the sound.

If you were to amplify exactly the sound of a metal string vibrating on a solid hunk of wood (e.g., a Fender Telecaster), it wouldn't sound very interesting. However, each element in the chain, from the electromagnetic pickups on the guitar, to the tube amplifier, to the speakers, are designed to modify and colour the sound. What we recognize as the sound of an electric guitar is not a faithful reproduction of the sound of that vibrating string - far from it - but a sound rich in particular kinds of overtones, attack and decay transients, and so on. Furthermore (and every guitarist knows this), a tube amplifier responds differently depending on the way you play (the way you touch the strings, pick, and so on), particularly when it is running really "hot."

As several folks have pointed out, there is now a huge cottage industry in tube guitar amps, and most of them are more or less reproductions of 1950s/early 60s guitar amps, with some modifications which make them more versatile in modern performance situations. Also, the days of giant stacks of huge amplifiers are now over and no one but the most stubborn of heavy metal dinosaurs goes there. Much more common is a low wattage tube amp, just like the 50s and 60s, but now miked and run through the PA.

For all you amp nerds, just for the record, my amplifer is a 1960 Fender Concert 4x10 (brown tolex) with a "voice of God" tremolo. I have a matching Fender reverb tank from the same era. Sounds like honey.

Kirk Keyes
07-14-2008, 10:34 AM
If you were to amplify exactly the sound of a metal string vibrating on a solid hunk of wood (e.g., a Fender Telecaster), it wouldn't sound very interesting. However, each element in the chain, from the electromagnetic pickups on the guitar, to the tube amplifier, to the speakers, are designed to modify and colour the sound.

Especially when you put a DOD FX-56 "American Metal" pedal in the middle of that chain!