DCP looked lifted

[Ernest Savage]

Hello,

After reading a 100 or so blog posts, I think I have this answered, but I have a few questions.

Background:

Shot Arri Alexa ProRes 4444 2k – ingest into Resolve – grade – output to Bluray DVD/web for festivals screeners and finally to DCP for digital projection at film festivals.

System config:

Resolve 10.1 – Decklink Extreme – HD-SDI via BNC cable – Panasonic BT-LH 2600W.

The process I should follow?:

I understand the difference between Rec709 video levels 64-940, and full range data levels 0-1023. From what I’ve read in the blogs, If I’m viewing through my HD broadcast monitor (the BTLH), then I need to set resolve to Rec 709 video levels 64-940). After grading, the DCP house says I should render out full range TIFFs (since they are 16 bit and DPX is lower, 12 bit, or 10 bit). The DCP house will then convert my blacks from 64 to 0 and my whites from 940 to 1023. The DCP house says they should able to match my look within a 4% margin of error.

My questions:

When I set Resolve to Rec709 FULL RANGE, instead of VIDEO LEVELS, I see the darker blacks, in my BTLH. What am I seeing? The image seems to represent more accurately what I’m seeing in my internal resolve scope. In other words, when I bring my blacks close to 0, and Resolve is set to rec709 full range, the image in my BTLH looks like the blacks are close to 0. When I set to video levels, my image looks washed out compared to what my internal scopes are representing. I know Resolve always works in 0-1023, but what am I seeing in the monitor? Can the BTLH represent 0-1023? I’m pretty sure not, but hoping some how it does.

Should I just work in Rec 709 video levels, use external scopes, and let DCP house adjust my blacks and whites? How will chroma be affected?

Thanks, you folks are a wealth of knowledge.

[Mike Most]

>>Should I just work in Rec 709 video levels, use external scopes, and let DCP house adjust my blacks and >>whites? How will chroma be affected?

I’m glad you asked that question at the end of the post, because the answer to that is yes. Assuming they know what they’re doing, the company making the DCP should be able to apply transforms for the three major differences between your Rec709 targeted material and the digital cinema format. Those three things are color space (including white point), gamma, and running speed (23.98 to 24) for both picture and sound. Your knowledge base and your equipment seem to let you work in video space just fine (assuming you’re looking at a properly calibrated monitor). But digital cinema is not video space, and having them ask you to go “half way” by delivering 12 bit TIFF files – even though they will, by definition, be in the wrong color space and have the wrong gamma – tells me that either they are giving you bad direction, you’re asking the wrong questions, or both.

What you need to do is turn out a video product you’re happy with. What the company making the DCP for you needs to do is take that video product – in whatever format you deliver it (I would suggest either DPX sequence, uncompressed Quicktime, or Prores4444, with 5.1 audio either embedded or separate), but with the knowledge that it is in video space – and make a DCP that projects on a standard DCI compliant projector and looks virtually identical to your video product on a properly calibrated video monitor. How they do that should be irrelevant to you. “Do it yourself” only works if you really know what it is you’re doing, have the equipment to do it and test it properly, and want to take on the responsibility of it being compatible with the intended distribution venues. If you are hiring a company to do that for you, you should not be doing anything to alter what you know how to make properly, because in doing so you are essentially taking on responsibility that should be theirs. If they don’t see it that way, you might want to look elsewhere.

[Juan Salvo]

Of course all that requires proper 709 viewing and pipeline, with a calibrated display and a high degree of confidence. Otherwise even the most experienced DCP author won’t be able to make your film look right, cause it’s been graded under whatever conditions it might have been. GIGO.

https://JuanSalvo.com
https://theColourSpace.com

[Margus Voll]

Proper DCP houses take your 709 video level files and deliver proper DCP.

Your display chain should be correct and then i see no problems.

We do it here on daily basis with Clipster or with software and the results are accurate.

—

Margus

https://iconstudios.eu
https://vimeo.com/iconstudioseu/videos

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[Ernest Savage]

Thanks for the confirmation. Several people have chimed in and all agree. Work in Rec 709 video levels (64-940) and let DCP house make the conversion. They say there will be about a 4% difference in contrast and chroma. Hopefully it’s not enough for a regrade.