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Kodachrome and gray card question


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#1 Chris Burke

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Posted 29 June 2006 - 09:24 PM

Hi,

I am shooting a friends wedding Friday afternoon and evening on Super 8. I plan to shoot the afternoon stuff on Kodachrome and the evening festivities on Tri-x pushed 1. I am going to shoot a gray card for both stocks. My question is should I tell Dwayne's to time to the gray card for the kodachrome. I know that card is more for the telecine, which I plan to do, but didn't know if that info would help the Kodachrome at the lab.


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#2 Nathan D. Lee

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Posted 29 June 2006 - 09:27 PM

From what i understand there is no color timing done to kodachrome. Its reversal therefore the first time the image will be visible is after it has been finished. Really the only thing you can tell them is to push / pull etc... the grey card will only help the telecine which would be your "color timing" phase so to speak.
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#3 Chris Keth

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Posted 29 June 2006 - 10:23 PM

From what i understand there is no color timing done to kodachrome. Its reversal therefore the first time the image will be visible is after it has been finished. Really the only thing you can tell them is to push / pull etc... the grey card will only help the telecine which would be your "color timing" phase so to speak.



Yeah, a greycard would just be for telecine purposes. There isn't anything a lab tech can do with reversal in the process anyway that would require a greycard, save perhaps if you had it cross-processed but then the greycard would likely not be grey anyway.
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#4 Hal Smith

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Posted 30 June 2006 - 12:17 AM

Am I missing something? I'm under the impression that after a reversal film like Kodachrome goes through first development that the film is "flashed" with light to expose the print layer. It may not be possible to change the intensity or color of that light in any current, practical film processor but at least in theory that light could be adjusted in the same way printer lights are adjusted for a one-light print from negative film.
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#5 David Mullen ASC

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Posted 30 June 2006 - 12:33 AM

How could you know how much to adjust the flash if you don't even know what the image will look like until it's finished developing? By design, it has to be a standard, automatic process to reverse the image. Besides, I doubt the flash can be used to readjust the density of individual positive image silver layers, especially if the initial negative process gets rid of the color filter interlayers.
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#6 John Pytlak RIP

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Posted 30 June 2006 - 05:43 AM

A gray card does NOT provide any information that allows a lab to adjust the process for a camera original film. Once the film is processed, the gray card provides a reference for the color timer / grader / colorist when a print or transfer is made.

A lab can adjust the process time/temperature to push/pull a process, but this is done by request, and not because of any measurement of a gray card image on the unprocessed film.
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#7 Hal Smith

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Posted 30 June 2006 - 07:19 AM

How could you know how much to adjust the flash if you don't even know what the image will look like until it's finished developing? By design, it has to be a standard, automatic process to reverse the image. Besides, I doubt the flash can be used to readjust the density of individual positive image silver layers, especially if the initial negative process gets rid of the color filter interlayers.

The way the process works currently you wouldn't. The simplest improved method might be to run the equivalent of a snip test. You'd shoot a gray card, snip it off the head end of the shot, process the test, then adjust the flashing lights accordingly to process the rest of the shot. Obviously there would have to be a three color, adjustable flashing light in the processor - something that probably doesn't exist at present. I personally like the look of Ektachrome (I'm a patsy for saturated color) and would love to have a way of "tweaking" it beyond camera and light filtering. I confess I'm sympathetic to a parallel to Dogme philosophy, experimental film where you edit and project the camera original, something that would be suicide in any professional environment.

Maybe if this was the 1960's and film still ruled the world there would be a possibility of Kodak getting interested in such a system. But they're obviously most interested in investing in the remaining strong markets for film which I'm afraid doesn't include reversal films. Kodak still sells enough Ektachrome to keep making it but the traditional large markets for reversal like news film have dried up.
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#8 Sam Wells

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Posted 30 June 2006 - 08:39 AM

It's an interesting idea, playing with the re-exposure,but I'm not sure you wouldn't be just as well off pre (exposure) or post flashing the Ektachrome instead of doing it in the developing process.

Flashing the Ektachrome EF films; 7242 etc was quite common in the seventies; most labs offered it.

Otherwise I think you're in DIY lane with an E-6 kit...

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#9 John Pytlak RIP

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Posted 30 June 2006 - 08:40 AM

"Development by Inspection" was sometimes used with old blue-sensitive or ortho films, which could be examined under a safelight as they developed. Not really a practical method today, where consistency and quality in processing are most important.

For motion pictures, Kodak reversal films provide an alternative "look", and still service a "niche" market where filmmakers want to project their camera originals. But color negative film has been the mainstay of professional motion-picture production.
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#10 Charles MacDonald

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Posted 30 June 2006 - 09:40 PM

Am I missing something? I'm under the impression that after a reversal film like Kodachrome goes through first development that the film is "flashed" with light to expose the print layer. It may not be possible to change the intensity or color of that light in any current, practical film processor but at least in theory that light could be adjusted in the same way printer lights are adjusted for a one-light print from negative film.



Kodachrome has a VERY Complex process. They reexpose one layer through the back with a filter, then develop it, the expose the front though another filter and develop TAHAT, and then the thrird layer is fogged chemicaly and developed. Each layer get the colour dyes added when it is developed, so that is why the have to be done one at a time. IF you were very cleaver and had a LOT of time to run tests, you might be able to play with teh re-exposure on the front and back, but I suspect taht since there are different speeds of film in teh same process (at one time there was a Kodachrome 200 Slide film) I would guess that process is set up so the exposure normaly is sufficent to fully exposue every remaining grain in each layer. the chemicasl fog would otherwise be able to find undeveloped grins on the front and back, which would at the very least give a cast

Ektachrome standard process (E6) uses a chemical reversal step, so again it does not offer any latitude to play with re-expsoure.
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#11 Hal Smith

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Posted 30 June 2006 - 11:21 PM

Thanks to all for their input - I appreciate everyone's comments.
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#12 Tim Terner

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Posted 30 June 2006 - 11:43 PM

I know stills photography is different but when we used to shoot 20 rolls of positive film on a job (all shot under the same lighting and at the same F stop) we'd always have 4 to 5 rolls clip tested before making a decision on whether a slight pull or push was made. All processing labs offered this service. Strange it's not available with cine processing
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#13 David Mullen ASC

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Posted 30 June 2006 - 11:53 PM

I know stills photography is different but when we used to shoot 20 rolls of positive film on a job (all shot under the same lighting and at the same F stop) we'd always have 4 to 5 rolls clip tested before making a decision on whether a slight pull or push was made. All processing labs offered this service. Strange it's not available with cine processing


Sure it's available in cine processing. You could snip off the head of a roll, process it, print and project it, and decide whether to push or pull the remaining roll. Trouble is to make sure that you're not clipping off a scene, just a gray scale or card at the head of the roll. But push/pull processing is normally in one-stop increments, and considering the wide latitude of color negative, we don't need to adjust processing in small amounts to correct the density, and for the wide adjustments, we know BEFORE we shoot the roll whether it will need to be pushed or pulled, assuming we know how to use a light meter. We have to be consistent because you have to process all the rolls for a scene the same way to keep the color and contrast consistent. It's not like stills, where each shot usually stands on its own, plus it's not like reversal where you have to get the density right in the final processed image and the format has limited exposure latitude. With negative, you have the printing step or the telecine transfer to make final density adjustments so micro-managing the processing is not necessary.
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#14 Chris Burke

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Posted 01 July 2006 - 12:26 AM

A gray card does NOT provide any information that allows a lab to adjust the process for a camera original film. Once the film is processed, the gray card provides a reference for the color timer / grader / colorist when a print or transfer is made.

A lab can adjust the process time/temperature to push/pull a process, but this is done by request, and not because of any measurement of a gray card image on the unprocessed film.



thank you John and everyone else. Just what I needed to hear. Just got home from the shoot, loads of fun shooting a wedding on Kodachrome on a pier next to the JFK Library. They are going to love it. Instant nostalgia. Shot the gray cards for both stocks. The lab which is dong the Tri-X is doing the tk for everything. I get that it is for their benefit only. Got great light for the exterior. Interior was a bit of a bitch. Very dark. So I did have a 26 element LED strapped onto a stroboframe with my camera. I am going to push 1 for one role and push 2 for 2 others. I hope I get something. Shot at 9fps wide open. Had no choice. It was dark. I did bring a Tota for a couple of obligatory shots like the cutting of the cake and such. But as expected, they didn't like it too much, so I did my candid stuff with the led. I could see some difference in the view finder but not much.

I do not mind grain at all, neither do the couple. It will live on video. How much can I expect of Tri-x pushed 2?

chris
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#15 Chris Burke

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Posted 01 July 2006 - 12:38 AM

thank you John and everyone else. Just what I needed to hear. Just got home from the shoot, loads of fun shooting a wedding on Kodachrome on a pier next to the JFK Library. They are going to love it. Instant nostalgia. Shot the gray cards for both stocks. The lab which is dong the Tri-X is doing the tk for everything. I get that it is for their benefit only. Got great light for the exterior. Interior was a bit of a bitch. Very dark. So I did have a 26 element LED strapped onto a stroboframe with my camera. I am going to push 1 for one role and push 2 for 2 others. I hope I get something. Shot at 9fps wide open. Had no choice. It was dark. I did bring a Tota for a couple of obligatory shots like the cutting of the cake and such. But as expected, they didn't like it too much, so I did my candid stuff with the led. I could see some difference in the view finder but not much.

I do not mind grain at all, neither do the couple. It will live on video. How much can I expect of Tri-x pushed 2?

chris



David,

I didn't see your post. I guess a clip test may be the way to go.

chris
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Broadcast Solutions Inc

rebotnix Technologies

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Aerial Filmworks

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