Scopes and ODTs

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Simon Rabeder

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Scopes and ODTs

PostSat Feb 04, 2017 2:44 pm

My scopes inside of Resolve seem to change depending on whether I use Rec709 or P3-DCI ODT. Why is that, am I not seeng stuff as it is handled within resolve?

I am confused by this as the monitored picture looks really similar depending on using 709 or P3 (switching ODTs and monitor calibration).
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waltervolpatto

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Re: Scopes and ODTs

PostSat Feb 04, 2017 4:56 pm

roughly that seems the correct behavior: let's say that you have a perfect white D65 in Rec 709, and you change the output ODT to p3Dci white point, because the actual measured 100% white on a dci white is greener, if you simply map 100% you will have a perceptual difference on the monitor.

so, the math is done in a way on the monitor the white looks about the same. in your scope it will look a bit more on the magenta side.
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Simon Rabeder

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Re: Scopes and ODTs

PostSat Feb 04, 2017 10:53 pm

The odd thing is, that BMD say that the internal scopes are meant to represent the internal processing diregarding the range and gamut of the output. Why wouldn't this virtual white point be mapped to whichever white point a gamut defines? It is clipping at certain values in the scopes anyways.
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Marc Wielage

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Re: Scopes and ODTs

PostMon Feb 06, 2017 12:26 am

You can avoid this problem by using external scopes from the actual monitor output. External scopes have two other benefits: 1) it takes a little bit of the load off the Resolve GUI, and 2) it gives you the flexibility of arranging the scopes in any layout you prefer: big, small, wide, narrow, high, low, etc.
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Simon Rabeder

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Re: Scopes and ODTs

PostMon Feb 06, 2017 11:00 am

Would be cool to be able to choose where the scopes sit. I'd like them to show white as an absolute and not depending on the output. Just for reference when doing balancing. For now I will just do the first pass in 709 and go P3 (if that's what the output is going to be) later on.
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waltervolpatto

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Re: Scopes and ODTs

PostMon Feb 06, 2017 12:36 pm

Simon Rabeder wrote:Would be cool to be able to choose where the scopes sit. I'd like them to show white as an absolute and not depending on the output. Just for reference when doing balancing. For now I will just do the first pass in 709 and go P3 (if that's what the output is going to be) later on.


the "absolute wire" depend on your output. you want an oxymoron.
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Simon Rabeder

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Re: Scopes and ODTs

PostWed Feb 08, 2017 1:19 pm

Does this mean P3 can show values brighter than white that are not neutral?
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waltervolpatto

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Re: Scopes and ODTs

PostWed Feb 08, 2017 8:46 pm

Simon Rabeder wrote:Does this mean P3 can show values brighter than white that are not neutral?


no, it mean that the [1,1,1] white on P3 in in the XYZ color space a "greener " white than rec 709 "D65" perceptually

but it is still a white.
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Simon Rabeder

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Re: Scopes and ODTs

PostFri Feb 10, 2017 10:10 am

Thanks Walter for taking the time :)

Does this green offset affect all of the image or only the white? Meaning, do the mids and shadows also need to have a green shift?

Is this because of projection technology? (like server needs to hand the projector a greenish signal for the xenon to produce perfect whites)

Is there any good literature on this that you can recommend? I don't wanna have to ask you all these questions. I am really interested in getting more into P3 stuff (understanding the different white points).

Up until now I graded mostly in ACES and log workflows, just went ahead and graded in 709 and then changed the ODT to P3-DCI later. Do you have any objections to this?

What a lot of ppl do and I also did on occasion is color managing a 709 master to a P3 output. Any comments on this practice?
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waltervolpatto

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Re: Scopes and ODTs

PostFri Feb 10, 2017 6:15 pm

Simon Rabeder wrote:Thanks Walter for taking the time :)

Does this green offset affect all of the image or only the white? Meaning, do the mids and shadows also need to have a green shift?

Is this because of projection technology? (like server needs to hand the projector a greenish signal for the xenon to produce perfect whites)

Is there any good literature on this that you can recommend? I don't wanna have to ask you all these questions. I am really interested in getting more into P3 stuff (understanding the different white points).

Up until now I graded mostly in ACES and log workflows, just went ahead and graded in 709 and then changed the ODT to P3-DCI later. Do you have any objections to this?

What a lot of ppl do and I also did on occasion is color managing a 709 master to a P3 output. Any comments on this practice?


no, the black are pinched at black, the gray scale will get perceptually greener COMPARED to a D65 white. but it does not matter: once you do the DCP properly, is a WYSIWYG system (unless you create out of boundaries colors).

forget about "perfect white" it does not exist. a 3200K white that rest on the black body curve IS white. e are just "used" to think that rec 709 D65 is "white"...
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Simon Rabeder

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Re: Scopes and ODTs

PostSat Feb 11, 2017 7:58 pm

Yes I am aware about the whole planck thing. Also that it is a relative thing. But a green shift that's changing with brightness? As I said, can you point me to any literature or sources of any kind, just do I can read into it.
I will probably learn to work with it in practice though. Still would be nice.
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waltervolpatto

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Re: Scopes and ODTs

PostSun Feb 12, 2017 3:54 am

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Simon Rabeder

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Re: Scopes and ODTs

PostWed Feb 15, 2017 9:07 am

Thank you Walter, I appreciate it.

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