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Grading Film for film print, DCP and Rec709 for TV broadcast

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Aaron Hayden
Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 7:10:09 pm

To preface this, I usually work in Rec709 for TV.

I have film that needs to be graded for flim print, DCP and HDcamSR for TV broadcast.

Source footage is Alexia 1920x1080 Prorez4444.

My plan is to grade in Data Level colorspace with my Flanders LM2461W set to DCI P3 mode. I have a tektronix 7020 scope, when grading in data level do I just ignore 0-700 IRE scale? I'm assuming that I can use the full range beyond the limited scale of video level Rec709.

Output DPX RGB 10bit for film print and DCP. That's format the lab is requesting.

Now that I graded the entire film in data level P3 colorspace, what is the correct/fastest/best way to convert the grade to Rec709 for my output to HDCAMsr?

Thanks in advance!

Aaron Hayden


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Mike Most
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 7:34:29 pm

The easy answer is work in Rec709 colorspace, since you say it's what you know how to do, and it's clearly what you're set up for since you don't have a projection environment. Any other approach is going to add complication and a lot of room for error, and not really bring a lot to the table.

In talking about any approach, it is important to identify which deliverable is the primary one, and which are the secondary ones. You have to target one and convert for the others. You should talk to the lab (whatever lab you're using) and ask them if they are set up to use Rec709 as their input format for both the DCP and the film print. Most reputable labs can do that pretty effectively. There is no real point to targeting P3 unless you are fully set up to do so (and that really means a projection environment, even if the monitor is technically capable of displaying P3), understand the implications, have a proper conversion LUT to get you to Rec709 for the video deliverable, and really understand what you're doing. The color results yielded from working in Rec709 and P3 are not night and day on either the DCP or the film print if the proper conversions are used, which in your case would be the lab's responsibility. Don't try to do things you aren't really qualified to do with the experience and equipment you have if there is another path that is just as appropriate.


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Aaron Hayden
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 8:27:39 pm

Thanks for your insight Mike.

The rec709 workflow you suggested is exactly what I originally wanted to do. I would love to grade rec709, have the lab convert for film, use my finished rec709 grade for my hdcamsr output. Unfortunately the client is insisting to evaluate my grade in P3 color space do to the lab's comments that P3 would most accurately translate to what the final film print will look like, (the film print is the primary delivery format, rec709 secondary). The lab did say they can handle conversion from rec709 to film print and DCP.

I have a film out test coming up to verify what I see in my bay will translate to the film print. I would love a way to prove to the client that grading in rec709 would in the end match any grade I did in P3.

Tell me if this is a good idea or not. Grade a scene in rec709 for the lab to convert. Grade same scene in P3 and see if it matches the converted rec709. If it matches then it proves that I can grade in rec709 and trust what they see in my bay in rec709 will translate accurately to the film print.

On another note, does anyone know where I can find a P3 to rec709 conversion LUT?

Thanks again.

Aaron


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Aaron Hayden
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 9:19:11 pm

Also, Is my FSI 2461w monitor completely unsuited for DCI p3 monitoring and a projector is the only way to reliably view DCI p3?


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Mike Most
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 11:33:12 pm

It sounds like your "client" is demanding things based on buzzwords and not on reality. It also sounds like they've gotten some questionable advice.

Accuracy in film recording is based on accurate 3D transforms, regardless of whether those transforms are based on Rec709 or P3 input values. An accurate transform from Rec709 is much more preferable than an inaccurate transform from P3 space. There are out of gamut values in both of those spaces compared to that of film, and colors that will not be perfectly reproduced. What your client doesn't seem to understand is that P3 is a colorspace that was designed for display in a dark environment on a reasonably large screen with a specified brightness. It was, in fact, developed based on the characteristics of the TI DLP Cinema projection devices. Your perception of the image is significantly altered when you display those colors, that brightness, and that white point on a direct display 24 inch monitor. Displays don't exist in a vacuum, they exist in environments appropriate to the display type and the colorspace being used. You can turn off all the lights in the room and black out the windows, but if you do, the blacks won't be accurately perceived and the saturation won't be correctly perceived because it's not designed for that type of display or environment. In many ways, I'm really sorry that the LCD manufacturers have seen fit to include the ability to display P3 colorspace on their devices, because the notion that your perception of the result is the same as watching the image in a projection environment is very misleading, and creates the type of situation that you're experiencing right now. Doing various tests won't really prove anything, but it might make your client understand that they're not "losing" anything by allowing you to work in the proper colorspace for the equipment and environment you happen to have.

If you do need to convert P3 to Rec709 (although, obviously, I don't recommend that unless your working environment changes) you can probably obtain one from either Light Illusion (http://www.lightillusion.com) or Cinespace (now owned by THX, http://www.thx.com). Or, if you're a masochist, you could use the color management included in After Effects, which does this pretty effectively provided you understand how to use it.


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Aaron Hayden
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 4, 2013 at 12:24:32 am

You rock Mike! Thanks for the Lut links.

Ideally I get to work in Rec709, but at this point I'm preparing for both scenarios.

My bay is pitch black sans the glow the console, monitors and the Ideal-Lume Pro Bias Light hanging off the back of the Flanders. I have a 60inch plasma in the room as well but I'm pretty sure it can't do P3. In your opinion, what is the best monitoring solution at this point to view P3 in a median/small room? Reading through this forum, I feel I'm not the only colorist working in a median/small room on material destined for the big screen.


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Mike Most
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 4, 2013 at 4:08:47 am

There isn't any "best" solution that isn't a projector. The only one I've seen that comes even remotely close to being "acceptable" is the Dolby monitor that is over $30,000. Everything else is equally bad. Any colorist working under the conditions you're describing is doing themselves and their clients a disservice whether they realize it or not. And while that is admittedly only my opinion, it's based on reality.


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Joseph Owens
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 8:03:04 pm

[Aaron Hayden] "Source footage is Alexia 1920x1080 Prorez4444." (sic)

If you were really aiming to use an ACES workflow, it would make sense to jump through all the flaming hoops that the film/DCP target space would require, but given this source format, as Mike suggests, won't give you any more room than you already have without re-processing the values all over the place for no compelling reason. If the transforms are not dead on, it is worse than wrong, its a waste of time and undermines the entire effort.

jPo

"I always pass on free advice -- its never of any use to me" Oscar Wilde.


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Aaron Hayden
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 3, 2013 at 9:57:26 pm

Hi Joseph,

I did some research on the ACES workflow but I wasn't sure if all the bugs were worked out in Resolve. I found a couple of older posts on this forum referencing some issues. I also was afraid of conversion issues when roundtriping to the VFX house using ACES.


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Joseph Owens
Re: Grading Film for film print, DCP and Rec709 for TV broadcast
on Jun 6, 2013 at 3:20:13 pm

[Aaron Hayden] "I did some research on the ACES workflow"

Makes you wonder why anyone would use the word "salvation", other than in the context of "I'm glad someone else has to make this work".

So when someone asks you to take a casual stroll through a known mine field... well, its probably not even safe to say "after you", since some of them have counters that are armed to take out the third or fourth person to step on it.

jPo

"I always pass on free advice -- its never of any use to me" Oscar Wilde.


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