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Grain and color of VNF stocks


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#1 Marc Roessler

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Posted 24 June 2012 - 07:32 AM

Hi everyone,

I was wondering why the VNF stocks (7239, 7240, 7250, 7251, ..) have so poor color, sharpness and grain (even back then when fresh stock was still available). Are these effects inherent when designing a low-contrast reversal stock, or is it just because those are old emulsion designs?

Has anyone ever tried pushing Ektachrome 100D (7285) 2 stops to EI 400? Would this look any better than the true 400T 7250 VNF?

Greetings,
Marc
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#2 Chris Burke

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Posted 24 June 2012 - 08:16 AM

Hi everyone,

I was wondering why the VNF stocks (7239, 7240, 7250, 7251, ..) have so poor color, sharpness and grain (even back then when fresh stock was still available). Are these effects inherent when designing a low-contrast reversal stock, or is it just because those are old emulsion designs?

Has anyone ever tried pushing Ektachrome 100D (7285) 2 stops to EI 400? Would this look any better than the true 400T 7250 VNF?

Greetings,
Marc


Yes, because they were older stocks with dated technology. I have not pushed 7285, but my educated guess is that it will look better than 7250. the main reason for this is because any 7250 you might have is very old now and may have fogged. 7285 is modern stock with modern technology at work. BMW Films "Powder Keg" used 7239 I think and it looked great.
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#3 Marc Roessler

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Posted 24 June 2012 - 03:54 PM

Chris, do you know any details about the post processing used? The BMW spot didn't look like typical 7239.. was this done digitally? Reminded me a bit of a bleach bypass look.

Edited by Marc Roessler, 24 June 2012 - 03:54 PM.

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#4 Charles MacDonald

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Posted 24 June 2012 - 09:15 PM

Hi everyone,

I was wondering why the VNF stocks (7239, 7240, 7250, 7251, ..) have so poor color, sharpness and grain (even back then when fresh stock was still available).


The VNF stocks were designed back in the 60s- 70s for a specific market. Television News. TV stations had been using 16mm cameras to shoot new film for the local newscasts, but their was a demand for colour film and so the VNF stocks were designed with special "Fast" processing.

No doubt the contrast was optimised for the Telecine chains used in local TV stations, If one was looking for a film to use as a master for eventual multi-copy relase, there was the old standby Ektachome Commercial.
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#5 Brian Drysdale

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Posted 25 June 2012 - 02:53 AM

No doubt the contrast was optimised for the Telecine chains used in local TV stations, If one was looking for a film to use as a master for eventual multi-copy relase, there was the old standby Ektachome Commercial.


They were projection contrast and you needed to be careful with losing the shadow detail. I know people who did get prints made from VNF, they weren't too bad, but they were no where near the quality of the prints from the neg stocks.
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#6 Mark Dunn

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Posted 25 June 2012 - 04:52 AM

We used it extensively for a certain type of military high-speed cine, 7250 IIRC, pushed 2 stops to 1600. It was the only stock that would suffice.Presumably they use video now. I do know that when VNF disappeared certain civilian high-speed cine users simply lost their ability to shoot colour.
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#7 Charles MacDonald

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Posted 25 June 2012 - 03:20 PM

Presumably they use video now. I do know that when VNF disappeared certain civilian high-speed cine users simply lost their ability to shoot colour.



I actually had the impression at the time it disappeared that it was the other way arround, that some high speed users were mandated to use a digital format by the regulators who were requiring the High speed photography and so the market dried up leading to the stock being cancelled.

VNF was available to the end in Polyester base, with 2R High Speed perfs. (3000) which are only used for High speed cameras.
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#8 Chris Burke

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Posted 25 June 2012 - 06:56 PM

Chris, do you know any details about the post processing used? The BMW spot didn't look like typical 7239.. was this done digitally? Reminded me a bit of a bleach bypass look.


it does look like bleach bypass or cross processing. I think it may have been done in a lab not DI, but I don't know for sure. That film was my favorite of the bunch.
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#9 Richard Tuohy

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Posted 26 June 2012 - 03:21 AM

it does look like bleach bypass or cross processing. I think it may have been done in a lab not DI, but I don't know for sure. That film was my favorite of the bunch.

If you bleach bypass with the normal colour reversal process, you have 100% silver - ie the negative image developed silver from the first developer, and the positive image developed silver from the second (chromagenic) developer. So, if its bleach bypass processed, it must also be cross processed using colour neg chemistry.
...which leads me to think, you could theoretically retain the silver from the second developer if you used a black and white bleach (like R9 or R10) after the first developer. This would remove the developed silver from the first developer, but not affect the remaining silver hailide which is then processed in the second developer. You could then skip the normal colour bleach and then just fix. Must try that.
richard
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#10 Mark Dunn

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Posted 26 June 2012 - 03:53 AM

I actually had the impression at the time it disappeared that it was the other way arround, that some high speed users were mandated to use a digital format by the regulators who were requiring the High speed photography and so the market dried up leading to the stock being cancelled.

VNF was available to the end in Polyester base, with 2R High Speed perfs. (3000) which are only used for High speed cameras.

I don't know about that, I'm talking about the UK and recall talking to a certain civilian user who certainly wasn't being told to use video.
We didn't use polyester base. It wouldn't break in the event of a jam and that would have been a disaster at 5000pps.
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