Photography - Variable Density Greyscale Film for audio

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Variable Density Greyscale Film for audio

Hi:

I like using variable-density analog B&W negative film optical tracks
for audio. The audio characteristics of the film make my mouth-water.
Yes, for some wierd reason, the film's audio makes me hungry.

Audio signal, in the form of light changing its intensity in a
analogous manner to the sound, is shined onto a negative film. The film
is developed and playback is accomplished by shining light of a
constant intensity onto the developed film. As the light goes through
the film, the patterns on the film will change the intensity of the
light that is received by a photoelectric cell. The change in light
intensity results in a changing electric current which is sent into an
amplifier and then to a loudspeaker.

http://www.mtsu.edu/~smpte/twenties.html

"The Tri Ergon Process uses a technology known as variable density,
which differed from a later process known as variable area. The Tri
Ergon process had a pattented flywheel mechanism on a sprocket which
prevented variations in film speed. This flywheel helped prevent
distortion of the audio. Tri Ergon relied on the use of a
photo-electric cell to transduce mechanicalsound vibrations into
electrical waveforms and then convert the electrical waveforms into
light waves. These light waves could then be optically recorded onto
the edge of the film through a photographic process. Another
photo-electric cell could then be used to tranduce the waveform on the
film into an electrical waveform during projection. This waveform
could then be amplified and played to the audience in the Theater. The
Fox Film Corporation acquired the rights to the Tri Ergon technology in
1927. "

The ERPI system, Fox-Case's Movietone, and De Forest's Phonofilm use
variable-density recording film audio

Regards,

Radium

Variable Density Greyscale Film for audio

On 2006-09-20 20:27:41 -0700, "Radium" said:

The ERPI system, Fox-Case's Movietone, and De Forest's Phonofilm use
variable-density recording film audio

But, no one makes variable density sound recoding film, nor do the labs
know how to process VD properly.

And, I'd bet nearly every WECo RA-1231 ever made has been converted
from its original VD mode to VA mode, and to Stereo Variable-Area, at
that.

RA-1231s are still in new production, and are pretty much as WECo
designed them in 1947, and with the valve as WECo designed in 1937, but
changed for SV-A.

Variable Density Greyscale Film for audio

peterh5322 wrote:
On 2006-09-20 20:27:41 -0700, "Radium" said:

The ERPI system, Fox-Case's Movietone, and De Forest's Phonofilm use
variable-density recording film audio

But, no one makes variable density sound recoding film, nor do the labs
know how to process VD properly.

7302 will work acceptably well. I have run it through an Auricon
sound recorder and just processed in neg chemistry for a gamma of around .6
and it didn't sound all that good, but it was okay.

And, I'd bet nearly every WECo RA-1231 ever made has been converted
from its original VD mode to VA mode, and to Stereo Variable-Area, at
that.

I would not be surprised if there are some folks with the WECO and RCA
sound cameras that still had a VD mode to them. Quite honestly, if
you just stick a diffuser behind the slit, you get VD.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Variable Density Greyscale Film for audio

mono and VD.

That bears repeating. ;)

Variable Density Greyscale Film for audio

mono and VD.

That bears repeating. ;)

Yep. Those 2 are "fidelity" problems.

Variable Density Greyscale Film for audio

In article mNoRg.806$KK.532@trnddc08,
"Morgan Montague" wrote:

mono and VD.

That bears repeating. ;)

Yep. Those 2 are "fidelity" problems.

Boo.
Go to your room.

P.S. -- verrry good.....

Variable Density Greyscale Film for audio

peterh5322 wrote:

But, no one makes variable density sound recoding film,

Yup! But if you can get enough light, 2234 dupe negative stock will
work. If you can't get enough light to expose D/N stock then finegrain
stock will work better than print stock, but the contrast is higher than
ideal.

5378 can be made pretty wide tone if processed in a super-low contrast
developer. In Technidol, I can get the gamma down to 0.65 but the ASA
rating drops down to 40.

2234 is SLOW. Grain structure is good, and the gamma is very low but
easily controlled. What's the approximate ASA or photorecording sensitivity
on that stuff? It's got to be insane. Less than 5366 even.

nor do the labs know how to process VD properly.

A few still do, but it is a dying skill.

Which ones, out of curiosity?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."