Lumetri Color and Picture Profile question

[southwestform]

Using PP CC 2015 and a Mac, I'm working with a bunch of clips that were given to me that were shot with different cameras.

1. Is there a way to figure out what type of Picture Profile the clips were shot with since this will affect how they are color graded?

2. I am trying out different Input LUT options in Lumetri Color. Do these LUTs stack on top of each other OR does selecting a new one cancel out all of the effects of the previous one?

3. After working with the different options in the Lumetri Color Panel I want to reset and start over. I see I can go to Effect Controls and choose the Reset Effect option for Lumetri Color. Is there another way of doing this without needing to go to the Effect Controls tab?

Thanks!

[R Neil Haugen]

1) "Picture controls" aren't something that is normally 'read' by NLE's. Except for some of the high-end cameras recording in specific formats such as Arri RAW, the Red formats ... and some of the say Sony or other Log formats. Even then, mostly it's a you-assign such things. Many of the colorists I know have their own home-built LUTs/Looks for various cams they work with regularly, including often having variants for studio, outdoor-nighttime, tungsten, that sort of thing.

Which cameras are you working with?

2) Selecting a different LUT replaces any earlier selected LUT in the same 'slot'. I would add, PrPro has a wrong application of the LUT position in the Input tab. That location is placed to be processed before any of the Basic tab controls, which is totally backwards from designed methods of the camera manufacturers and other apps such as Resolve, the most widely used colorist's grading app.

Camera "tech" LUTs such as log-to-Rec.709 conversions are built around using cameras in tightly controlled studio lighting. With nailed color-balance, contrast, and exposure. I could post any number of quotes here, but the designed use of such LUTs is to place them in the processing chain, then use the grading controls processed prior to the LUT to correct the media to fit the curves of that LUT as designed for proper neutralization.

In Lumetri, that would mean placing the tech/Log-normalization type LUT in the Creative tab's LUT/Look slot, then using the Basic tab to adjust for neutral/correct white-balance, contrast, and tonality. Real white-balancing is not possible however in the Basic tab as the white-balance controls there only adjust the relative gain ... the white-points ... of the R,G, and B color channels. It's a linear control change ... so the farther down the exposure you go, the less the WB controls affect things ... by the shadows, they do nothing visible. They make some difference in the mid-tones. So there will need to be corrections applied later in the 'chain'.

3) No. Which is why I move the ECP to the right into the same panel group as the Lumetri panel, just a different tab in that panel, so it's quick to get to without scrolling over the entire screen.

Neil

[R Neil Haugen]

A bit of addendum ...

• The Lumetri panel processes top-to-bottom both within tabs and between tabs. Order of processing can make a difference. The only thing out of order is the WB control (such as it is) of the Basic tab is processed ​below​ the contrast/tonality controls.
• You can add multiple "instances" of Lumetri by dragging Lumetri from the Effects panel to the timeline. They will 'appear' in the ECP ​below​ any previous Lumetri effects. These would add to what's been done above, and be processed ​after​ the effects above.
• When there are multiple instances of the Lumetri effect on a clip, the Lumetri panel ​only​ controls the ​last ... lowest​ Lumetri effect on the clip. To change the settings of previous Lumetri effects, you go to the ECP, and twirl down the controls, all of which are available there. But cannot be used with control surfaces such as the Palette or the Tangent Elements or Ripple panels.
• You can put an Adjustment Layer above a  clip, and drop Lumetri on it. That will be processed ​after​ the Lumetri and any other effects applied on the clip directly.
• Lumetri stacked in multiple adjustment layers will be processed clip first, next A-L up next, and each ​higher​ A-L will be processed in order ​going up​. Track 2 A-L before track 3, 3 before 4.
• Lumetri on different tracks all use the main Lumetri panel ​unless​ you add additional Lumetri on that track.
• Adding multiple Lumetri can bog down the computer. So for complex work that I'm doing in Lumetri, I'll typically make an instance with a bunch of corrections, export that as a .cube LUT, reset that layer; starting over, apply that LUT in the Basic tab, then do more work, applying things as needed, and if more is to be done, I'll export ​that ​whole 'layer' of Lumetri as a .cube LUT, reset, add that LUT (now containing everything I've done in the prior steps) in the Basic tab, and work another set of controls.
• Anything really needing too much of the latter ... you might consider a round-trip to Resolve, painful and tedious as that process is.

Neil

[southwestform]

I’m mainly working with footage that someone else shot from an A7SII, though some of it is Cine4, some Slog2 and some Slog3. When importing the footage, what do you do if you do not know if it was shot Cine4 or Slog2 or Slog3, etc.?

I have some LUTs that I want to install into Premiere so I can apply them to the clips. How would I know which to apply if I do not know the Picture Profile of how the clips were shot?

Thank you.

[R Neil Haugen]

If you're working with one camera person, advise them which seems to be the better over-all format, and stick with one format. I've no clue why someone would switch that much with one camera. It just makes a ton more work down the road in post.

The colorists I know work with all kinds of media ... much of course of the Arri, RED, and such rigs. But also some projects have a lot of DSLR and drone media included. They may have metadata on the camera used, but rarely the profile within the camera.

But that wouldn't matter much anyways ... they'll take a look at 2-3 of their home-canned LUTs for Log conversion, pick the one that works nicest without touching, then go. If the conversion gets pretty close, without clipping whites or crushing blacks or sending saturation out of bounds, it's fine.

I've made my own LUTs for the learning process, and the times I do get outside media to work with I still always use my own home-cookin' on them. Works great.

It would be nice if we could use the 'preview' feature of the Lumetri Creative tab to scroll through LUTs like you can with the included ones ... but since they changed the way the program 'sees' the LUTs in the Lumetri/LUTs/Creative folder to some sort of 'relative' process, putting our own LUTs in there is inviting confusion on exports. NOT good.

So ... there's a couple ways you can do this. First, put the LUTs in a folder/subfolder arrangement on disc. Use the "custom" option in the Creative tab LUT slot to navigate and it will go back there next time you choose it. Try one ... then try a second. See what you think. You should quickly get a relative idea of what the LUTs do compared to each other. And don't worry if the one for Slog3 looks better on an Slog2 clip than the 'correct' LUT. The only way to determine 'correct' in LUTs is what works on this clip right now. Don't worry about the name or precisely matching them with the camera & profile.

The other option, is to pic a "common" type of media of one of them, put it on a sequence, add the "appropriate" LUT in the Creative tab, and maybe do just a bit of futzing with the Basic tab tonal controls and saturation, even the Creative tab's vibrance control. When it looks 'neutral', with a decent tonal range and layout, moderate saturation/vibrance, nothing clipped or crushed ... save that as a Preset, named for the media/LUT combination.

Do that with each, and then you can just go to your Presets tab, twirl-down the Lumetri User Presets section, grab the appropriate preset and drag/drop it on the clip. Or select a number of clips, drag/drop and apply it to a group simultaneously.

With a tech LUT ... or even a Look style LUT ... you never go for perfection in the LUT itself, just close & clean. Then do your work to make it shine.

Neil

[southwestform]

What is the difference between a Tech LUT and a look style LUT?

[R Neil Haugen]

Tech LUTs are designed for technical 'corrections' ... like taking Slog-2 to Bt. (Rec) 709, that sort of thing. "Normalization" of log & RAW media especially.

A "Look" is something done for aesthetic reasons.

So Tech LUTs are best stored in one place, and Look LUTs in another ... each named for what they do.

Neil

[excited_Genie16B8]

The Input LUTs (TECH) will take the footage from the specified camera setting to a proprietary color space.  The Creative LUTs will take the footage from that proprietary color space to the designated "look".  They're designed to work together, and while they certainly can be used separately, your results won't be "correct" if you do.

[R Neil Haugen]

Looking through the 2018 offerings, there aren't the matched SpeedLooks sets such as there used to be. Those were pretty fun to work with, really. The tech LUTs there in 2018 are simply designed to get the media from a select few cameras into PrPro's Rec 709. Any one of them, or rollin' your own, can work if it meets the needs you have for the camera/media/project in question. Although as noted, in professional grading work, they must have tonal/WB neutralizing done with the LUT in place but the corrections to neutralize processed before the LUT.

As most of the colorists I know ... who teach around the world, btw ... "roll their own" tech LUTs, and their own Looks, apparently they aren't working correctly.

Neil

[peters10069509]

How would it be processed if you applied those basic grade adjustments on the actual footage clip in your timeline and then applied a LUT to an adjustment layer above the clip in the timeline? Would it then simulate the correct order of grading > LUT?

[R Neil Haugen]

Applying a Lumetri with a LUT in an A-L above a clip will be processed after the clip ... which is quite useful.

One of the problems with the Look sort of use in the current Lumetri is that a print-emulation LUT/Look is applied in the beginning of the Creative tab. Think about it ... you are trying to mimic a 1970's soft shadow/long-tapered highlights movie look. You have a LUT or a Look file designed to take a full-range Rec709 signal to that shape. You apply it.

Now ... do anything to affect the image after that ... and you've changed the look. You no longer have that specific look anymore.

So ... that is best applied either in an A-L above a clip/sequence, or as a last instance of Lumetri on the clip itself. You can go to the Effects panel, type "Lum " in the search, and should already see the Lumetri effect listed. Drag it onto a clip or A-L, and if there's already a Lumetri 'there', it will be put in the ECP after (below) the other Lumetri.

In general, for basic grading work per clip, one adds Lumetri to the clip as needed. Lumetri can start hammering playback performance, and so sometimes I'll do a bunch of work in a Lumetri layer, export that Lumetri from the 3-bar "hamburger" menu as a .cube LUT, and in another Lumetri that I'll be doing further work in, import that .cube in the Input slot of the Basic tab, and do more work that will of course be after the work I've put in that LUT. I've done this through a couple times so I've ended with 5 layers of Lumetri down to 2 layers. One on the clip, one on the A-L above the clip, saving a lot of playback issues.

For playback, it's good to have that Look instance of Lumetri on the A-L turned 'off' with the eyeball at the beginning of the sequence in the header bar. Get your clips of a scene neutral compared with each other. Get your scenes proper to each other, daylight clips looking their way, interior shots looking right, all pretty neutral. And occasionally turn on the over-all "look" layer to check how it blends.

Neil

[southwestform]

Last questions:

1.) what happens if I am working on one computer with my LUTs installed and take my external drive with the media and project file to another computer without the LUTs installed on the second computer. Will the video open up and look the same as it did on my computer even without the LUT installed on the other computer?

2.) after applying a LUT and color correcting and color grading the clip, how do you simply copy all of the adjustments to another clip?

Thanks!

[R Neil Haugen · Accepted solution]

1) No. You need to either have the LUTs on that drive, and install them on that computer and navigate to them, or ... as JIm Simons advocates here, store your LUTs on your CC subscription account cloud libraries, so you can access them directly from any computer to which you log into your CC account.

2) Right-click on the clip, "copy" ... and then when you get another clip or clips selected, right-click/Paste and choose Lumetri effects in the options box. You can also save any Lumetri settings as a preset, named in your Presets/User Presets bin, and apply from there.

Neil

[excited_Genie16B8]

1. There is not.

2. & 3. Lumetri Color Panel Explained - Premiere Pro CC 2015 - YouTube