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Photochemical grading for DCP


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#1 Sanji Robinson

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Posted 11 October 2016 - 01:42 PM

Hello,

 

I wonder if anybody has attempted to take the OCN and grade it photochemically using printer lights, then make a best light print and then scan that print for the DCP?

 

I can imagine the characteristics of the print stock would be embedded in the scan (contrast, grain and color). Obviously there is no/limited digital post flexibility once you scan the print.

 

Could this workflow yield some interesting/unique results or can the look be exactly replicated by scanning OCN and using a print-stock emulating LUT?

 

Any thoughts welcomed!


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#2 Kenny N Suleimanagich

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Posted 11 October 2016 - 02:52 PM

There are lots of home video releases (VHS, DVD, Blu Ray, VOD) done from scans of IPs; they often have visible grain and deep blacks. At this point, almost anything that can be done photochemically can be done with grading and grain emulators like Livegrain. 


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#3 Sanji Robinson

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Posted 11 October 2016 - 03:11 PM

Nolan don't seem to agree.

 

They did an all photochemical finish on Inception and they'd even telecine the print which is what I am talking about:

 

"The editors were working with an HD telecine made from a film print (not a negative), and the director was screening dailies in 35mm scope every night plus Avid screenings of the evolving cut, through a Christie 2K projector, every Friday. "
 
"We telecine’d the print. So we didn’t telecine the negative. For all of our major screenings, we have a conformed 35mm workprint. "
 

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#4 David Mullen ASC

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Posted 11 October 2016 - 03:53 PM

The DCPs for Nolan movies are usually made from a color timed IP after the answer printing is finished. Projection contrast prints are too hi-con for a decent transfer other than for a work print purpose, not for exhibition. "Batman Begins" was scanned at 6K from a color timed IP for the IMAX DMR release.
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#5 Sanji Robinson

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Posted 11 October 2016 - 04:30 PM

David Mullen, what are the advantages of doing a color timed IP from the OCN and then scanning that?

 

Versus just scanning the OCN and doing the rest in the digital world.

 

Does the photochemical grading yield a higher quality or more "organic" image?


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#6 David Mullen ASC

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Posted 11 October 2016 - 09:22 PM

No image advantages -- the IP is one generation removed from the o-neg, so it is slightly softer, grainier, and maybe dirtier (though that is digitally cleaned up.)

 

It's just that if you are going to do a photochemical finish in order to get a print, then you end up with a negative with splices in it, sometimes even an A-B roll spliced negative, so it becomes simpler & safer to transfer from an IP at that point rather than run the spliced negative through the scanner, though that's done often for restorations.

 

There is a cost advantage in the sense that color-correcting a scan of a color timed IP will go faster than color-correcting a scan of original negative.

 

You could say that the scan of the IP will "feel" more like the print version since fewer digital tricks will have been used to color-correct it, since the goal is generally to just match the look of the print.


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#7 Sanji Robinson

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Posted 12 October 2016 - 04:10 PM

 

 

The DCPs for Nolan movies are usually made from a color timed IP after the answer printing is finished. Projection contrast prints are too hi-con for a decent transfer other than for a work print purpose, not for exhibition. 

 

When you say IP, do you mean intermediate stock or print stock? Intermediate film is quite low-con, low-sat.

 

Are projection prints too high-con because of the generations removed from the OCN or because of the nature of the print stock?

 

Another question: how would one excatly replicate the high-con high-sat print look of this "Death Proof" trailer:


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#8 David Mullen ASC

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Posted 12 October 2016 - 09:30 PM

Interpositive has the same contrast as camera negative. Print stock has very high contrast in order to achieve black blacks when a bright light is shining through the print and the image is projected on a white screen. Contrast is added to a scan of camera negatives (or interpositives or internegatives) using LUTs when making a DCP or Rec.709 video master. Contrast is also added with basic color correction tools.

Roughly speaking you have about 14-stops of information on a negative and about 10-stops on a print or a home video master or DCP. If you actually use a print for making a home video transfer, you essentially have no flexibility in color correction and your shadows seem to drop quickly to black or look milky from trying to let detail out of them. Now in the case of something "retro" looking like "Death Proof" sometime the filmmaker wants to emulate the harsher look of a print transferred to video and might actually use a print for transfer. Or they'll create that print look in digital post.

Camera negatives are "low con, low sat" as you say because they are designed to be printed from. If that were a problem, then why would anyone shoot on camera negative stock? The wide dynamic range image which gets scanned into a log form, which when viewed on a Rec.709 monitor without a correction LUT looks pastel, milky, washed out, is not a "flaw" it's an advantage.

You have to give up this notion that a log scan of camera negative, IP or IN, looks "wrong" because when viewed improperly looks low-con and low-sat. It's supposed to be that way because it's designed for either making a print or for applying a viewing LUT to correct the gamma for a video screen or digital projector.
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#9 Mark Dunn

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Posted 13 October 2016 - 06:30 AM

OP, if you haven't seen the effect, try shooting some digital stills in RAW format and viewing them in something like Picasa (not the Windows viewer, that applies a jpeg-style correction- a LUT, if you like). They usually look very flat, but they can have a lot more dynamic range than a jpeg.


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