About show LUTs and Daily timing

[LucaM]

Two questions in a row!

1) thanks to Stip i understood the difference between Show LUTs (for shooting) and Look LUTs (for post production). I hope the terms are correct. My question: how do you create a Show LUT, if It’s in pre production? With tests shoots?

2) What’s the role of a Daily Timer? Is a role existing also with digital production or Is limited to film?

Thanks in advance and sorry for the boring questions!

Topic

[dmullenasc]

On many shows, the dailies colorist gets the footage, either shot raw or something like ProRes, converts it from raw if necessary, applies the LUT being used on set for the monitors, applies any shot by shot image adjustments to the LUT sent in by the DIT usually as ASC CDL values, probably applies any letterboxing needed, and outputs in the deliverables that editorial needs and whatever is used for streaming dailies. They will also back-up the data.

[dmullenasc]

Not sure what the difference is between a “show” LUT versus a “look” LUT unless a look LUT refers to things in post like a Vision 2383 print LUT as a base for correction so you don’t work outside of the color gamut that print stock can create.

[LucaM]

Thanks David, you’re always very kind!

 

You are right, my poor phrasing made the question a bit confused. I was referring to this thing Stip explained to me in another post:

Stip wrote:

Look development of a project is usually done before shooting. Colorists call this “Show LUT”. The main driver is mostly the contrast curve and saturation, then there might be some hue rotations or tinting of shadows, highlights. This ‘look’ is applied to all scenes. The LUT is loaded into cameras/monitors and the project is shot under it. Costume or set design choices should be made under the show LUT as saturation and density changes can change a color’s appearance…

So, if i understood, the show LUT is loaded in the camera and the scenes are shot with the LUT on, to obtain in real time an effect close to the final one.  What confuses me is that, being little experienced and self taught, i noticed a common trend around the web, i mean the suggestion of use a LUT for post production (what i roughly called “look LUT”) to speed up the grading (or at least have a decent starting point), but i’ve seen really rarely mentioned the show LUT created. It seems more reasonable and logic to have a “pre” LUT and work around that, instead of altering everything with a “post” LUT (you know, those like “Famous Movie Look LUT” that are everywhere around the web). So my doubt is that if it’s a common practice to use both a “pre” and a “post” LUT, or if the latter is just an unprofessional quick turnaround.

[dmullenasc]

The same show LUT could be used for set monitors, dailies, and then as a starting point in the final color-correction with the likely option to start from scratch and go back to log or raw, but use the show LUT as a reference. LUTs might be loaded into some cameras or the camera sends a log image to the DIT cart and the LUT is applied there and sent out to all the other monitors, or it might be loaded into individual monitors.

But this might be separate from technical LUTs like for viewing in P3 versus Rec.709, or working within the gamut for 2383 Vision print stock for a film-out.

 

[Stip]

So my doubt is that if it’s a common practice to use both a “pre” and a “post” LUT, or if the latter is just an unprofessional quick turnaround.

I think calling it “pre” and “post” LUT might be confusing as ideally they should not be two different ones. Rather think of it as “customised” versus “non-customised” LUTs.

“Show LUT” is basically just a word that is commonly used by colorists for a custom look that is then saved as a Look Up Table (LUT), so that it can be used in-camera while shooting.

Camera tests are being made to check if the LUT introduces unwanted artefacts under various circumstances, to assess if it looks and feels right or e.g. to make wardrobe decisions, as their appearance can change due to hue shifts and saturation changes.

As David pointed out, the “Show LUT” (custom LUT) itself then can be used in post or act as a reference while grading is done from scratch. There is no right or wrong here. If I remember correctly the LUT for “The Joker” was used in post as it was crafted very well and acted rock-solid (Jill and Mitch Bogdanowicz). Another famous  “Show LUT” (custom LUT) example is Roger’s own, which I believe he shot every movie since 2011 under and gave the “look” to all of them.

The point of an in-camera Show LUT is that decisions on set translate well to the final look (of course you will still use your eyes and meters on set, not just the monitor). You don’t have to create a custom LUT for that, you could use any LUT you like – just decide on the look before shooting and don’t fundamentally change it in post – that’s the whole trick.

Which is probably what you meant with “pre” and “post” LUT: to use e.g. a standard Rec.709 camera conversion LUT while shooting but then apply some Look LUT in post. This can still work but it’s less ideal in my opinion.

[Stip]

“Show LUT” = custom look LUT that is used both during shooting and in post (directly or as reference).

[LucaM]

Thanks again Stip! Somehow, even if with my poor camera and poor technical knowledge, It’s (more or less) what i did for my short, i did many test, set the picture profile and in camera Rec709 preview  (it has no LUT preview but somehow i built it with settings). Little knowledge but a bit of  old school common sense, ah ah!

So the LUT Is created from the initial tests in pre production, is It correct?

[Stip]

If you have old footage of the same camera/colour space you want to shoot in you could create it with that.

[Author]

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