Log color workflow - master clip LUT's to adjustment layer causing issues

[benb70691813]

Hello,

I'm working with ARRI LOG footage with intention sending the footage to a colorist to apply color adjustments. I'm not finishing in Premiere.  I've been working with an input LUT applied as a master clip effect to each clip to give me rough idea of what the footage will look like. Ive gone about cutting and adding various effects and transitions and some compositing, both in Premiere and AE.

I'm now preparing the footage for the colorist, and finishing VFX work. I want to deliver a flattened LOG Quicktime. To get there I have disabled the input LUTs that were applied as master clips effects, and applied the same input LUT to an adjustment layer over all the footage, as a top layer in my sequence. I'm doing this so I can make my entire sequence, footage and the effects applied, translated into the flat LOG color.

The contrast and color curves added by the LUT on the adjustment layer is now messing with the effects. Which I anticipated, but I'm finding it pretty hard to correct. In particular cross dissolves, or any layering of color solids with opacity changes, especially if blending modes are set to something other than "normal". Screen or Add modes behave very differently with a LUT over them. Its not always easy to fix it either.  Its rarely just an issue of increasing the opacity by 20% or something. And it seems that sometimes in fixing it, reducing the contrast etc, it I also introducing artifacts, like banding and noise, into the image.

The same holds true in After Effects, but it is a bit easier to fix there. My experience is AE compositing algorithms are usually much better the PPRO. But its still a pain there too. I've tried adding input LUTs that do REC709 to LOG to the graphics and solids, but it doesn't really work. Maybe i'm not using the right input LUTS though? The LUTS I'm using on the camera footage is the "Alexa Default LOG to REC 709" and the "Alexa V3 K1S1 LOG to VIDEO DCIP3 EE"

Is there a strategy you would recommend for how to go about translating the effects work done in premiere (and AE for that matter) to LOG?  I'm really hoping its not true that if you are going to apply any effects or dissolves etc to LOG footage in Premiere, you have to finish it in premiere. But I also cant imagine how else the master clips would work.

An example to reiterate the problem: Take some LOG footage, apply a input lut to it. Place a white color matte on top of the footage, make the white matte in "Add" mode, and create a ramp from 0-100 opacity. View result. Now disable the input LUT on the clip, and place it on an adjustment layer above both the clip and the white color matte. It will look different. How do you fix it so that a colorist down the line can apply a LUT to the clip and it looks as it should?

Another issue, when rendering the preview within premiere with the LUT applied on the adjustment layer, it looks different than when I export it. Same settings for preview/sequence setting and export (ProRes 4444)

Any help is greatly appreciated, thank you!

[Jim_Simon]

I'm unclear why you're trying to 'fix' things.  You removed the LUT used for preview editing.  You're done.  Send it off.

[benb70691813]

The problem is the effects are not done in LOG color. So if a colorist applies a LUT to the finished comp (LOG footage + Effects flattened in one file), the effects which were done in linear color get a LUT applied to them as well.

In preview editing in PPRO the layering of effects processing is:

1) Bottom Layer: Footage in LOG

2) Middle layer: LUT on footage (footage now displaying linear)

3) Top layer: Effects, dissolves, etc

Now in preparing for colorist, to simulate what the colorist will have to work with, the order is:

1) Bottom Layer: Footage in LOG

2) Middle Layer: Effects, dissolves, etc

3) Top Layer: LUT

This reordering cases the composites and FX stuff to look very different.

It is my understanding that all footage brought it a colorist is typically flattened and in a consistent color space. Because how can a colorist apply color adjustments to different parts of a composite image?

[R Neil Haugen]

Before even starting the project, you should have had a detailed communication with your colorist as to what ... and how! ... they want the "package" delivered for their conform process. They have very specific and detailed wishes ... including which method you use to scale media or do time-ramps, as if you do this in certain ways it is much easier for them to maintain the scale & speed changes in Resolve. (Assuming Resolve.) And they'll tell you what they expect for the sort of thing you're asking about also.

I've been told by a colorist that "Inexperienced 'new' clients try to guess, and their projects are a nightmare. Experienced 'new' clients always ask detailed questions ... and it's so much easier."

The colorists I know ... and the material available on the MixingLight.com site ... assume that cameras and FX will come from PrPro for conforming as separate color/space items. One of the first jobs of the conform is to sort media by type, so log gets basic log-treatment, VFX which could be in who-knows-what color space ... by individual clip no less! ... gets put into the common space for the project ...

And then after that is taken care of in the conform process, then they start the grade.

So ... the stuff you're doing would actually mess their expected workflow, as they do not expect the log media to have a linearization already applied, nor do they expect the  FX stuff to be the same color or even space as the media.

Neil

[benb70691813]

Thank you Neil.  Yes I regret not talking to a Colorist at the beginning, however, I haven't hired one. I am certainly an experienced client trying to guess.

So to clarify, then the process outlined here (which is for After Effects, but same principle for PPro), is incorrect? Understanding Log and Color Space In Compositing

[R Neil Haugen]

Part of the interview process with the colorist is getting their process list for how they want things delivered. Anything you do to try & prep yourself without that info is probably wasted time.

Ask one or more colorists.

Neil

[benb70691813]

Got it, thank you.

[Jim_Simon]

if a colorist applies a LUT to the finished comp (LOG footage + Effects flattened in one file)

That would be the wrong way to send it to the colorist.  For best results, he'll want the original media to color, without transitions or effects.

[benb70691813]

Thanks Jim. Am I wrong in assuming that in a standard post production workflow color timing is done as a final stage? Or is color done first, then VFX?

I don't understand how complex compositing or even less complex VFX work can happen if the colorist needs to be able to work on the original media, then apply the effects IN the color program. That changes how the effects look.  For instance lets say I have footage shot in LOG, that I then take into After Effects and build a complex composite with many layers, and elements not shot in LOG. How does the colorist deal with that?

Lets say I'm making a transformers movie. I've got my talent shot in LOG on a green screen. Then I've got megatron and the environment etc built in CG. These elements will end up overlapping in all sorts of ways. How is color dealt with here?

[R Neil Haugen]

Colorists have to deal with that everyday ... it's a regular and expected part of the job. And Jim's right, for everything not VFX, they'll want original media to conform to. And they're used to structuring the process during the conform to handle the VFX and other types of things like that.

For many colorist jobs, the conform ... where they ingest all the media, sort out what kinds of media they've got, organize all media & assets into tons of bins, check time ramps & scaled media processes, all that sort of thing ... is up to a third of the total job time. You might as well ask if you should expect an editor to know how to create a project in PrPro.

Ask a colorist how they want it delivered.

You're wasting time and energy trying to sort this out ... that's their job, including telling you how to deliver for best work.

Neil

[benb70691813]

This video was super helpful and demystified this whole process: https://www.provideocoalition.com/after-effects-and-alexa-part-2/

The bottom comment also address mixing colorspaces in the composite.

Still unclear how this works in Premiere, but I guess I will do any FX work over in After Effects then.

[R Neil Haugen]

Any colorist worth working with wants to be consulted as early *in the editing process* as possible. *Your* choices for doing time ramps, scaling, and a number of other effects can add hours to the conform process on their end. This can blow either your cost (billed per hour) or their ability to pay bills on the job (quoted price) right out the window.

There are certain ways to handle such in PrPro that make life easy in Resolve or whatever program they use. Some ways make the conform a longer, harrowing process.

Having a major project that is from the beginning assumed to be going to a colorist without prior experience with that colorist just show up is seen as a clear sign of a lack of professional experience if not a total disrespect for a fellow professional.

When my colorist friends talk about getting projects from editors with no prior experience delivering to *their* shop, who just want to "dump" a project on them, they aren't reticent about comments on working with noob editors.

Scathing comments.

I have no understanding why any professional is unwilling to work appropriately and respectfully with other professionals. You surely aren't saving money on the grading this way.

Neil

[benb70691813 · Accepted solution]

Bruh, if I had a colorist to speak to, and if were a seasoned professional having navigated this workflow for the 50th time, I surely wouldn't be asking these questions on an Adobe forum. Relax.

For anyone else trying to navigate this topic, over at creative cow I've gotten more answers: LOG color workflow with effects in PPRO : Adobe Premiere Pro

The workflow I'm basically following is detailed here: The VFX behind "Äkta människor" (Real Humans) // GeneralSpecialist

Which is summarized here:

1. Import ProRes4444 with default settings (no color management, no ‘Preserve RGB’ or anything.)
2. Create Adj. layer with “Apply LUT” and choose “LogC2Video” LUT created in Arri’s LUT Generator, to match the on-set look of Rec 709.
3. Set the LUT Adj. layer on top of every comp, and set it to a Guide layer so it doesn’t render.
4. Any RGB sources get a “Apply LUT” with a “Video2LogC” LUT applied to them.
5. Comp in 32 bpc and view everything with the “LogC2Video” LUT.
6. Render out to ProRes4444 at 32bpc. Since the “LogC2Video” LUT is a Guide layer, you just “Add to Render Queue” and hit Render.

Yes, absolutely, talk to the colorist first. If you can.

[R Neil Haugen]

Great info there ... and sadly, I'd note, it's not based on something from the Adobe help/tutorial materials. Which is something that's been asked about many times before. Ae is setup to do some color managing, if not nearly as much as say Resolve ... and it seems to me if PrPro had more color management options, those needing to work this kind of system might have a much better working experience.

Granted, it would be for some subset of users akin to giving a 4-wheel drive pickup to someone with no 'woods' experience, and letting them go drive off into the woods. Chances are, they'll just get themselves in a lot deeper before someone has to come pull them out.

But in a professional video editing program, well ... that kinda goes with the territory, if you're going to give the respect to the users to be professional in the media & processes they need. They need the tools. I've filed the feature requests for more color management options ... not only for situations like yours, it might be useful, but geez ... the range of monitors and color spaces being used for serious suites is rather cool these days, and sRGB/709 is somewhat ... limited.

Does this process render out a file for the colorist to actually work, rather than serving as a 'guide' video while providing the original media for them to correct?

And full apologies for any slights that may have occurred ... I'm so used to the majority of people here asking questions in the way you started being ... rather more a noob, to be polite. Had I realized you'd had as much experience as you do, my comments would necessarily have been different ... my assumptions were simply wrong.

Thanks of course for posting such a useful set of guides for working with this media. I'm hoping eventually it won't be such a hard thing to get info on using the app for the work it seems to have been intended for.

Neil

[Roei Tzoref]

this workflow can work for simple cases but will create a problem in others. it's still a valid workflow for simple inserts, but compositing in Log is not recommended by professional standards, and instead you should composite in Linear. there is OCIO which is a free plugin that allows you to do that. 

[Roei Tzoref]

Here's a relevant tutorial for managing color in After effects

https://www.youtube.com/watch?v=dHY5rMnBUz8