This is taken from the ACEScg Discord server community - from the #acescg-guide channel.
This is a good summary of ACEScg in practical:
• ACES (default, as non-CG) → ACES 2065-1 → the largest gamut and is referred to as AP0 (ACES Primaries 0). DO NOT USE AP0 FOR RENDERING! Use ACEScg = AP1. used for archival copies and transfer material between departments.
For more information, check this post from the ACES central forum: What am I rendering AP1 or AP0?
• ACEScg: Intended to be a working space for compositing and cg. The ACEScg specification, S-2014-004, defines a 16-bit or 32-bit floating point color encoding corresponding to linear exposure values encoded relative to the ACES AP1 primaries. The AP1 primaries lie near the spectral locus and encompass the Rec-2020 gamut and the DCI-P3 gamut for a range of white points. The AP1 primaries are within the ultra-wide AP0 primaries, used for the ACES2065-1 color encoding,and are well-suited for lighting, rendering, and compositing applications. Source: http://duikerresearch.com/wordpress/wp-content/uploads/2015/09/ACEScg-Digipro-2015.pdf | In some software ACEScg is also referred to as AP1, which stands for “ACES Primaries 1”.
IDT - The must know
If you don’t pre-convert your images to get the correct primaries then they will look off and incorrect.
• Utility – sRGB – Texture: for your LDR (low dynamic range) aka 8bit textures: Color (Albedo/Diffuse), Specular etc…
• Utility – Linear – sRGB: for HDR (high dynamic range) images like HDRIs IBL and all files with a linear transfer function within the sRGB gamut. Also valid for 16 bit EXR or TIFF files for instance.
• Utility – Raw: for scalar maps that need to be linearized when rendering such as: roughness, displacement, normal maps etc…
• Render in ACEScg and use OUTPUT - ACES sRGB, assuming that your monitor is in sRGB. If not, find out what your monitor is set to and use the appropriate ODT.
• Highly recommending the full guide from @ChrisBrejon https://chrisbrejon.com/cg-cinematography/chapter-1-5-academy-color-encoding-system-aces
• Also: https://acescolorspace.com
Additionally, this comment from: ACEScc vs ACEScct