LUTs and Lumetric colour

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Example I load a LUT into the basic section of Lumetri and it gives colour and brightness look "A" Let's say I can then remove this LUT and get the same look "A" with the Lumetri colour adjustments. Is this affecting the data in the same way?

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yes

Thanks for the answers. As the questions suggest what I'm trying to understand is:

Does the LUT do anything different to adjusting the controls in Lumetri colour?

Yes I know a LUT cannot be changed and I can only see what it did by looking at the affected clip.

Example I load a LUT into the basic section of Lumetri and it gives colour and brightness look "A" Let's say I can then remove this LUT and get the same look "A" with the Lumetri colour adjustments. Is this affecting the data in the same way?

I am sorry this seems to be such a basic question, it should be a yes or a no!

I hear people say "converting to Rec 709". I understand what Rec 709 is. However, the video file is a bunch of 0s and 1s. So this conversion is a nonsense, you're just affecting the data so it looks like Rec 709.

Thanks,

Jon

good points, neil, and appreciated, re: venues and workflow. documentaries are often like what you focus on... or industrials, etc.   shoot from the hip and after the fact try to get it edited and distributed ( no dailies, no rush, no giant production ). sorta... some docs can be funded and organized with a fixed end product and distribution already in place with editors on board ( like natl geographic etc. ).

anyway there is also a plain fact of life among people in general ( no matter the slot they have worked in .... editors, directors, producers, actors, etc.... )

everyone is capable of having different opions and it's nice to keep that door open.

well, I hope the poster doesn't just give up to learn some basic stuff as well as the more complicated stuff. first of all there is no such thing as an invalid question.

let's go to the beginning of the process of making movies and distribution.

a) shot real movie stuff on sound stages or location using pro cameras with or without luts from the camera to the SDI output of camera to monitors on set to let people SEE what the final product will be after post ( grading ). Sometimes called DIT. 

there is hardware to do that in the line ( output from camera to monitors) where lut can be applied without it coming from the camera ( no lut from camera , but added before monitor ).

If someone never experienced this process of shooting real movies on real sets to make a movie they will have no clue what this involves.

That's normal and understandable.

But the process is basically this....

a) preproduction

b) principal photography

c) dailies and post 

d) final delivery

the editor does not make the movie... they put the puzzle pieces together and work with producer to get the product for delivery. If they can't do it they get fired right away and someone else gets hired. the editor does not wag the dog.... the dog wags the tail ....

now that the poster is totally baffled by a lot of mud and misinformation about this subject it is unlikely they will ever come back to this thread. But it is important to note that this process is indeed a professional and long standing series of factory-like teamwork with the main goal of making a really nice product for distribution ( to make money cause it costs a ton of money to even START a pro movie process.... it's huge business... script, contracts, actors, locations, and yes, monitors on set to see what you want to have for distribution ( usually rec 709 which in post can be varied for different environments ( projection, HDR, etc. )...but to view it on set it is usually just rec 709 no matter what the main signal is coming out of the camera ( using lut boxes, etc. ).

there is no question that is invalid and now the poster will have to deal with what to do next with this knowledge....   maybe how to shoot, what codec to shoot, what color space to edit in, and so forth. Unfortunately the poster would have to supply some info about specific desires and equipment available to do all this.... and usually in this forum it is an iphone or gopro and youtube distribution... so it's probably moot to continue this thread.

getting back to basics I'm interested Neil how you would answer the question...

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1 - Is adding a LUT exactly the same as adding lumetri colour preset?

2 - Adding a LUT is the same as adjusting the controls within Lumetri colour?

3 - Adding a LUT does nothing 'magical' to the underlying data of the clip. It just changes the colour and brightness settings as per any other Lumetri change

1- no
2- no
3- yes if it's color space in general ( like log to rec 709 )

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if we keep it simple how would you answer the questions 1-3 ??

I'm just curious.... for the posters sake.

1 - Is adding a LUT exactly the same as adding lumetri colour preset?

2 - Adding a LUT is the same as adjusting the controls within Lumetri colour?

3 - Adding a LUT does nothing 'magical' to the underlying data of the clip. It just changes the colour and brightness settings as per any other Lumetri change

1- no
2- no
3- yes if it's color space in general ( like log to rec 709 )

see the definitions of luts and specifically the categories....

============ from link I provided.
Technical LUTs:

Display calibration: LUTs are used when calibrating monitors or other display devices for colour critical work such as editing or grading
Colour space conversion: LUTs that convert from different colour spaces, e.g. converting Rec 2020 to Rec 709
Camera LUTs: LUTs that are often created by the camera manufacturer to convert camera logarithmic formats that digital cinema cameras typically capture footage in (which look very washed out to the eye) into Rec 709 or Rec 2020
Creative LUTs:

LUTs can also be used creatively: for colour enhancement, creating monochrome or sepia effects, boosting shadows and highlights, or replicating the look of a particular film emulsion – the possibilities are endless.

LUTs can also be both creative and technical, such as those created by DIT (digital imaging technicians) and stored into ‘LUT boxes’ connected to on-set monitors that combine a camera LUT with a creative LUT. This is helpful for giving some idea to the film crew on-set of what the camera is capturing might end up looking like when it has been graded in post-production.
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there is a difference between resolve and PPRO with regard to how grading is handled. Nodes are used in Resolve and as you add nodes to make changes in grading those nodes only effect the clip they are applied to and don't change the lut or get cooked into a lut that was applied to the base color space for your project. it's just a next 'step' to adjust that clip. if you make a 'shared node' than that is about as close as it gets to lumetri preset. if you apply the shared node to all clips it does the same thing. but then if you want to change a clip with a shared node you have to add another node ( instead of changing the shared node which would effect ALL clips sharing it ) and make secondary grade adjustments to that clip.

A LUT is a look-up-table. A very simple concept, really. But using them can be amazingly complex and problematic.

In simplest form, you have a basic replacement chart. When the table specifies so, input value S becomes output value Q, and R becomes Z.

That's all they are, essentially. The link shown above gets into 3-D LUTs, where there are (also spelled out) extended options for X becomes Z.

They can be useful, and they can also be damaging. I work for/with/teach pro colorists, who call LUTs "the dumbest math out there" for a reason.

All LUTs are built with certain .. .expectations? ... as they are built for X media under Y condition ... even if you're not thinking about it when you make one. As that LUT will work as you expect but only when you feed it a clip like the one that was used to build it.

Same white balance, exposure, contrast settings in-camera and contrast of the scene ... all of that.

LUTs also need to be constructed ... and used ... for specific things. Which can be to change media from one color space to a different 'look' within that color space, or to change from one dynamic range or color space to another. The latter ... is very tricky, and any LUT for that needs a lot of testing to make sure it works adequately.

And color space and dynamic range conversion LUTs can not be used in Lumetri!

A lut creation app like LUTCalc (free, web-based) or Lattice can be set to build shoulders & toes with a long enough roll-off that you shouldn't get "clipped" (cut-off) highlights or "crushed" (cut-off) shadows. And can also be set to handle specific color space conversions. Which again, you should then test.

LUTs created within Lumetri

The LUTs created by the Lumetri effect are only able to do "look" changes.You can not do color space or dynamic range conversions within Lumetri at this time.

So things like the settings you've made in the Basic, Curves, and Color Wheels tabs can be 'cooked' into a LUT and applied to other clips quickly via the LUT/Look slots of Lumetri's Basic and Creative tabs.

LUTs from other sources

You can use LUTs from other sources, as long as they are one of the .cube type LUTs that the Adobe apps are built to use. Some "shaper LUTs" such as several of the ones that are included with Resolve do not at this time work within Premiere.

You cannot use LUTs within Lumetri as noted above to perform dynamic range or color space conversions. Any such LUT must be applied in the Color Management Controls process ... right-click a clip in the project panel, Modify/Intepret Footage, at the bottom in the CM controls ... Input LUT slot.

Storing your and acquired LUTs on your computer for use in Adobe video apps

There are a couple locations they have setup for all three Adobe video apps to check on launch for user-added LUTs. And you must use those, never ever ever add LUTs into the Program or Package folders with the installed LUTs!

If you look up their Online Help manual/documentation, they have a section on LUTs that has a chart with the two locations specified both for Macs and PCs.

My preference is the Progtram {Package on Mac) Files folder, Adobe/Common/LUTs ... note, this is the Adobe/COMMON folder and NOT Adobe/Premiere Pro folder!

Inside Adobe/Common/LUTs, there should be folders for Creative (Creative tab), Input (CM Input LUTs) and Technical (Basic tab). If there aren't, create them.

And store your LUTs there. In folders where you will use them within Lumetri.

My recommended use of LUTs within Lumetri

As LUTs are built for certain media, given a certain exposure/WB/contrast/saturation between camera and scene, there can be problems applying to other clips.

Such as if the exposure of the new clip is a little bit brighter, you may "hard clip" the highlights cutting off detail, or "crush" the shadows to black, again cutting off detail. You cannot get that detail back after the LUT is applied in the processing!

So it is at times necessary to "trim" the clip prior to the LUT so that the LUT works as expected. And this is easy to do if you apply the LUT in the Creative tab "Look" slot.

As then you apply the LUT in the Creative tab, and use the controls of the Basic tab (which are applied pre-Creative tab) to adjust the exposure, contrast, shadow, highlight, saturation, and black point to best advantage for fitting that clip into that LUT.

The difference between LUTs and Presets

A LUT is a baked-in set of image parameters. You can't change them.

A Preset is the actual effect ... in this case, the Lumetri effect ... saved with the settings as they were when you created the Preset, and named by you for what it does (hopefully ... ).

Lumetri presets are quite useful ... for example, you can drag/drop them onto selected clips in a bin, and therefore apply that preset on all of those clips in every place any bit of any clip is used in the project.

Or apply only to selected clip sections on a timeline panel, where they only apply to those bits as used on that sequence, but on no other seuquence in the project.

Presets can of course include LUTs in them too ... which is a great tool for applying adjustable changes as a "bulk" operation, saving you TONS of time.

And per clip, you can then go in and do the minor adjustments to make all the clips fit together.

Presets are a powerful time saving tool that also makes fitting your clips together visually a much easier, faster task.

Neil

read this...might help

WHAT IS A 3D LUT? – Brompton Technology