Grading Eterna 400T for HD, SD and Web

[Toby Tomkins]

The matrix is applied during recording, to emulate film, so the alexa logc rushes are comparable to film scans. It lets you use traditional film print LUTs and mix the alexa material with arrilaser film scans. As such, if using an alexa LUT for actual film scans, you would be better off using a LUT based around the matrix setting being on.

[Mike Most]

The matrix ***can*** be applied during recording, but that is optional and most often not done. In fact, many of us wish Arri did not offer that option because it causes a lot of confusion, just like it’s doing right now.

The reason for the film matrix’ existence is to provide better compatibility with traditional film DI pipelines and better results if you’re working with a film print emulation LUT. It is not intended for “general purpose” pipelines, and it is not intended for any color pipeline that does not include film print emulation as a specific target. The original poster specifically said he was intending this material for 709 type targets – HD, SD, and Web. I don’t see anything in there about a 3D film print emulation LUT, or film DI target. Color science doesn’t exist in pieces, it exists as a color pipeline. If you’re not using the back half of that pipeline, there’s no reason to use the front half except to confuse things and cause incorrect color combinations.

I’m not going to post any more on this, though. You seem convinced of things that I know not to be the case, but you’re entitled to your opinion.

[Toby Tomkins]

We’re both saying some of the same things Mike, and I totally agree about the film matrix option.

Francesco, experiment until you find something you like. Like I said before, there’s no right or wrong way to process your log files when going to Rec709, if it looks good to you, it works (-;

Mike, I’m sorry if I offended you, I’m only sharing what I’ve read.

Sadly you can’t ‘correctly’ use the arri lut builder with ‘film matrix on’ material, so this whole discussion is a bit of a moot point actually. Arri expects you to have your own pipeline for film material and your own LogC to Rec709 LUT. So you will need to find a generic Cineon to Rec709 LUT after all.

[Mike Most]

Well, yes, because Arri is not in the business of providing film targeted LUT’s, which really require specific negative and print stock emulations as well as assumptions about a lab process. A generic approach is not something Arri would support except as a general “look creation” tool, which is not the intent of the LUT builder. There are a number of print emulation LUTs floating around in various places for Cineon original if that’s what one wants. But nowhere in the original post do I recall anything being said about print emulation. All he wanted was a way to create 709 type material from film scans. That can be done any number of ways depending on the expected result, but I would point out that we have done telecine transfers from film to various video formats for many, many years and never had “print emulation LUTs.” Those only came into play when digital intermediate work began, and solely because the ultimate product of that process was a film print, thereby dictating that it be properly previewed. Film and electronic displays are different mediums, and you don’t need to emulate film to achieve pleasing electronic pictures. Just look at any television series shot on film either now (very few now, actually, but there are some: Breaking Bad, True Blood, Castle, Glee, Grey’s Anatomy, Boardwalk Empire – all of those are still on film) or in the past. That’s the product of original negative transferred to a video format, with no print emulation.

[Toby Tomkins]

Try this Francesco: https://www.motionfx.gr/generic-lut.html

[Mike Most]

Here are some pretty nice emulation luts (actually from a RedUser post…):

https://juanmelara.com.au/downloads/log2hd_cube_luts.zip

…….**IF** that’s what you want…. ;-D

[Toby Tomkins]

That’s a fair point, you could use redlogfilm LUTs, look at AntlerPost LUTs.

[Francesco Krattiger]

One more time thanks to all for your input.
I think I got somewhat of an idea as to how to proceed now, so that’s great!

Francesco