Rendering DPX from Color

[yvaineus]

Hi there,

I have color-corrected a 4K film trailer in apple Color and must deliver it to a post house for film-printing in DPX format with LOG color-space.

I was going to switch the render settings to DPX and the printing density to logarithmic, render, gather rendered-media, etc...

Are there important considerations regarding linear-->log color-space conversion that I am overlooking and/or ignorant of? Also, in general: what is the best workflow for preparing and delivering a DPX sequence for filmout in log color-space?

Many Thanks,
Evan

 

[Alex Hastings]

I wish I had the two hours to type and explain it too you. Maybe the company who is doing the film out can? You need to be Log from the begin or have enough head room to convert Lin to log. Maybe your 16bit Lin? If not, start over with log, luts from the film out company. And regrade.

If non of that sounds possible, deliver Lin then make the film
out company to the Lin to log. They can do it, they don't want to, but they can.

 

[yvaineus]

Thank you!

I suspected this to be the case.

However- given that my clients always want DVDs, Blu-rays and HDCAMs first, prior to film-printing, does this mean that I will always have to grade a film twice? For example, this particular project was graded in Linear and my exports have been quicktime files for DVDs, Blu-Rays, and various tape media... and now they want to print to film as the final step.

Have I essentially done this backwards? Should I first grade in log for digital cinema and then render out separate lin-based quicktimes for other non-film uses?

Thanks for your help

 

[Alex Hastings]

This is where the 2 hour long post comes in. Esentially it's about LUTs and proper software and proper workflow. Not sure how to explain it eseally.

You can esentially with proper workflow, hardware and luts be able to grade for Something like LIN rec709 and a film out at the same time.

Not sure what hardware software you use, but this is where Autodesk Smoke, Digital Vision Filmmaster, Filmlight Baselight, Quantel, Scratch and all the others are going to come in as your lifesaver.

How are you making your product with just FCP and Apple Color?

 

[jake blackstone]

Thank you!

I suspected this to be the case.

However- given that my clients always want DVDs, Blu-rays and HDCAMs first, prior to film-printing, does this mean that I will always have to grade a film twice? For example, this particular project was graded in Linear and my exports have been quicktime files for DVDs, Blu-Rays, and various tape media... and now they want to print to film as the final step.

Have I essentially done this backwards? Should I first grade in log for digital cinema and then render out separate lin-based quicktimes for other non-film uses?

Thanks for your help

Usually the grade for DCI performed first and from that Rec-709 copy is extracted for the DVD and broadcast. Nobody ever does two different grades. It would be prohibitively expensive and unnecessary. But this is not for casual user, requiring solid color management experience.

 

[Marc Wielage]

Nobody ever does two different grades. It would be prohibitively expensive and unnecessary.

Gee, I have on the 30+ Digital Intermediates I've worked on. They're not done from scratch, but they are two different grades (technically).

In general, we do the film-out pass first, get everything approved, then do a giant trim-pass for all the video deliverables. The LUTs are not transparent, not always predictable, and still need some tweaking. In truth, the video trim passes rarely take more than a day or two for each aspect ratio. If anything, the panning & scanning takes more time than trimming levels for video color space.

Your miles may vary.