Hello! So let's say i want to apply a fpe LUT for creative reasons. And i don't want it to tinker about with the contrast, i just want it to give me a colour response that that specific stock would give. I also want to apply it not as a LUT but as a 3x3 matrix in resolve with the channel math ofx plugin. Several questions to the pros here. Firstly how would i derive the matrix? Would this make sence and be better than just using a LUT? Does this sound totally insane and a complete and utter waste of time?

Thanks for the input

Stepan

With the non-linear response of film a 3x3 matrix will not work.
It doesn't have enough control of the variables.

Steve

And i suppose that converting the material into linear in a node prior to that would not work would it because you trying to emulate a non linear response in linear digital world?

I should probably say that the silly questions are ispired by Steve Yedlin's showcase of alexa vs film and wanting to understand what is he doing special with the footage that it is matches so closely on many different scenes.

stepanko

Yes! Can anyone else weigh in on their thoughts with this subject? Any information or guesses welcome.

What info are you after?
What Yedlin did is very simple to emulate - nothing special there at all.

It is very simple to profile film response and then generate a LUT to copy that exactly.
Or, as Yedlin has done, just use a 'generic' filmic response rather than one that is a profile of a specific film stock.

It is all just about gaining a 'look' that works...

Steve

Steve
Sorry for the confused and long questions, but after almost 7 months of uninterrupted search for similar information I'm euphoric to say that your last message and Look LUT design guide contradicted everything I believed to be true:
- Is it possible to have an accurate negative film emulation by scanning (using Cineon's specifications) a camera test (digital and film side-by-side) of a color chart in about 20 different stops of exposure and a variety of saturated lights; and then mapping the film stock's color gamut using non-linear math? I think that's how Steve made his two demos, and as far as I'm aware the best negative film 'emulations' available to buy use similar methods;
- Is there such a thing as an accurate emulation for halation, grain, gate weave, etc?

The only way to have an 'accurate' film match is to profile film stock, as we do with our film Profiling Service, using a very accurate hybrid spectroradiometer & densitometer.
https://www.lightillusion.com/film_profiling_service.html
The film data extracted can then be used to generate a truly accurate film emulation LUT.

Back in the DI days we would do a butterfly projection to prove the accuracy of such film emulations, with half the screen the original film projection, and the other half digital.
We had to do this, as the scanned DI work was cut back into the film maser, so the emulation had to match as perfectly as possible.

And halation, grain, & weave, is totally separate, and requires a very different approach...

Steve

Interesting. Thanks for your support.

Hello Steve,

First of all I want to thank you for your work, I love ColourSpace for tweaking LUTs!

I have a question, I don't know if this is already present in ColourSpace or if it would be possible to implement it. I hope you find my question of interest.

I would like to know if it would be possible to create the more compressed and contrasted aesthetic of a projection behavior with ColourSpace which we could add following one of your answers of film emulation LUTs with LUT tools.

I refer to this information from Harald Brendel inside The ARRI Companion to Digital Intermediate:
https://web.archive.org/web/20221002054219/http://dicomp.arri.de/digital/digital_systems/DIcompanion/ch02.html#id591490

Saul

saulmemeteau
Sorry, I don't really understand the question.

But, the D-LogE curves in the default film profiles built into ColourSpace are accurate to the combination of negative and print stocks.
If you want to change the D-LogE response, you can use the LUT Adjustment tools to do that.
For example, the 'Colour' tools.

Steve

Hello Steve,

Thanks a lot for your answer. It's normal that you don't understand my question because there is a concept problem on my part here. I clumsily thought that we could add a compression relationship which comes from the projection as an aesthetic result.

Have a nice day,

Saul

saulmemeteau
A projector's brightness capability just changes the contrast ratio from black to white.
You can add that into a LUT by using Limit Luminance.

Steve

Thank you Steve!

Steve
Would a DI or filmout be too questionable with that film scanning process? Is the problem due to the scanner being too variable compared to a film profiling system equivalent to yours? After watching the Steve Yedlin demo, I'm guessing the scanned film emulation LUT would be good enough for intercutting film and digital with more color grading.
Would a negative film LUT made by you work differently for a Sony Venice compared to a Sony-F55, for example? If I want to match both cameras to a film camera, would it be redundant to profile the digital cameras?