Working with ACES

[Jorge]

Hi,

Before I start, forgive me because I have seen that this topic has already been discussed in other posts but I still have doubts if I am working in the right way.

I usually work in advertising and I don’t usually have this kind of questions but lately I have had to work on a fiction project that is worked on in ACES.

I am using Flame 2025 2.2 and my way of working has been the following:

• I have created a project with the Color Policy in ACES 1.1.

• The shots come in EXR. I imported them leaving the Color Management in Tag Only (From File or Rules).

• I have done my compositing work without applying any LUT or Colour Management node.

• I exported the result as an OpenEXR sequence (16bit fp Zip multi-scanline).

After my work, the shots are conformed and colorized in DaVinci Resolve.

Is my way of working correct?

At the moment I don’t have an external monitor, I only have my main screen. How can I visualize on it the colors correctly when I work on ACES projects?

Thank you very much in advance for your help.

[allklier]

In general that is the correct setup.

One thing to look out for - if you are only using color space tags, none of the material is actually transformed into a new color space. So during your EXR sequence export you need to make sure that those EXRs are actually written in the color space you want to receive in Resolve.

In the export dialog there are some options to facilitate this color management. And presumably you may want to convert it to ACEScg.

Other than say Nuke, which always converts to the working color space, Flame only does that if told so.

[philm]

Don’t forget about matte edge softness.

[Jorge]

I thought that when exporting without using any transform color, the shots were already exported in ACES.

When exporting the shots in EXR, how do I choose ACEScg so that they can work correctly in Resolve?

Thank you very much for your help

[allklier]

I need to look into that a bit more.

I didn’t think that there are any implicit conversions on export. Maybe someone else knows the answer?

The dropdowns in export is only for input and view transforms.

More on this later…

[Nbjoin]

Something to clarify- you know your footage is in an ACES colorspace, but which one? There are multiple. It’s probably in one of these 3 colorspaces within the ACES system:

• ACEScg: AP1 primaries, linear
• ACEScct: AP1 primaries, log
• ACES 2065-1: AP0 primaries, linear

You will find tons of info on these different spaces on this forum and also on Logik Academy.

In short, you should be working within Flame with one of the first two, and you can easily switch back and forth between them depending on the task. Do your comping, blurring etc. in ACEScg to take advantage of the linear math. You can toggle over to ACEScct mid-schematic to resize, sharpen, or do any operations that break with values outside of 0-1. Most people also prefer to track in a non-linear space such as ACEScct or Rec709.

ACES works great as long as it’s always clear exactly which colorspace your footage is in, for you and also those receiving your footage. For this, it’s good practice to use a token to embed the colorspace within the EXR filenames and folder names.

[philm]

sudo dnf install -y openexr
openexr /path/to/my/openexr_file.exr

this will show you the values in header file, in which you may discover the file’s colorspace

[allklier]

@Jorge

I thought that when exporting without using any transform color, the shots were already exported in ACES.

When exporting the shots in EXR, how do I choose ACEScg so that they can work correctly in Resolve?

Thank you very much for your help

As promised, a follow-up on this.

The TL;DR is, no, EXR sequences aren’t always ACEScg automatically.

The details:

I took a SLog3 clip into a Batch (Flame 2026, ACES 2.0) and tagged is as Slog3. Then just wrote it out as an EXR sequence.

Test 1: I enabled ‘ColorMgmt’ in the media clip node, set to ‘Input’ as tagged.
Test 2: I disabled ‘ColorMgmt’ in the media clip.

In both cases the image looked correct in the viewer.

Below the output of exrheader of one frame.

As you can see in the Test 1, the resulting EXR file is in ACEScg. In Test 2, the resulting EXR is in SLog3.Cine.

In Test1, enabling color management on the media clip does transform it into the working color space, and then as such it gets written into EXR. If you don’t do this (default is ‘off’), you get viewing rules applied, but the data all the way through the export remains in the original color space.

That is Flame’s philosophy on color management. Don’t do anything to the pixels unless explicitly told otherwise.

To fix this and always write ACEScg during export, then in the WriteNode, where color mgmt is already on, but with a no-op, you need to change it to ‘Input’ from Source. Then your EXRs will be written in ACEScg, even if your comp wasn’t run in ACEScg (assuming that is your working color space, which is the default for ACES 2.0).