New to ACES and I need some guidance!


(antonkljungberg) #1

Hey!

So I’m trying to learn and use ACES for future projects, but I’m a bit stuck!
I’m mostly using the Blackmagic Ursa Mini Pro 4.6K, shooting in ProRes in “Film” dynamic range with firmware 6.0.

First of all, what should my settings be in DaVinci Resolve?
I’ve set Color Science to ACEScct v.1.1. IDT should be set to Blackmagic 4.6K V4 correct? Only problem is there’s only V3 despite it being the latest version of Resolve. Oh well, going with V3 for now…
ODT should be set to REC.709 (or whatever device I’m exporting for), correct?

The image after this looks alright, but I don’t understand the point of this. It’s almost impossible to get the contrast right, without blowing highlights or crushing blacks. The tools are so sensitive.

Are my settings off, or am I doing something horribly wrong? I find it quite hard to grade with ACES compared to DaVinci YRGB, and I don’t really see the point to grade with the ODT as one “looses” that LOG look to work with, even though it’s not destroyed, highlights seems to be clipping way earlier than when not using ACES?

Sorry for all the dumb questions!

Best regards,
Anton


(Fabián Matas González) #2

Hello Anton and first of all thanks for your question, I do think that while there is better understanding of how ACES works for Postpo/VFX workflow there is still a blank page on how We, the colorist should work with it. Main issue lies in my opinion on a wrong teaching on how you should grade Log encoded material whatever you’re or you’re not using ACES. The theory is when you using Log you should not use LGG wheels since they’re thought for Gamma/Video encoded footage.

In Log there is a step called normalization whose means is making footage look “nice” for your monitor, this process can be done generally by 2 ways, using a transform LUT(AlexaToRec709 for example) or manually, applying a curve and saturation. It’s important to understand that LGG controls should work properly after the normalization, and Log controls/Offset should be used before the normalization node. What happens in ACES, mainly there is no post normalization space since your “normalization” is the ODT( note I’m not using the terms properly but I think if I tell you like this is much more easier to understand), that means the correct practice to work in ACES is to use the Offset/contrast/pivot(contrast with the S curve disabled) to make all primary corrections. Now It can look like a big change of paradigm, but trust me, It’s really much faster and cleaner. To do secondaries you should use the log controls.

I hear Dado Valentic complain about how Log controls introduce noise, but I’m not sure if he was talking on a YRGB space, my humble experience is that in general you should only work with Offset/Contrast/Pivot, for exposure changes, sometimes I use the shadows and for some skin work I have used the midtones, but not usually. For developing general look I tend to work with midtones since I can play with both sides of the ranges(little bit like Baselight controls) and I overlap It using a parallels, so I can control the different ranges with colors and overlap them.

Note there is much more clever and experienced people around there and maybe some of the stuff I wrote is not accurate, but I can tell you at least this method helped me deal with around 50 pro works.

Cheers,