We are using ACES for a while, the color delivery between compositing and DI is reliable. For some reasons, we haven’t implement ACES color management in our whole VFX pipeline yet. So in compositing step, we have to deal with lots of sRGB/709 footage, and need to keep them looks identical as previous steps, such as MP or lighting, etc.
Here is some problems I met:
- When we import footage which have linear gamma with sRGB gamut, which IDT I should use?
This snapshot shows the comparison between a sRGB(gamma=2.2"approximately" & sRGB gamut) file and a “linear sRGB” (gamma=1 & sRGB gamut) file in the nuke-default color management, when “linear sRGB” imported as linear, and sRGB imported as sRGB, it looks identical.
This snapshot shows comparison between a sRGB(gamma=2.2"approximately" & sRGB gamut) file and a “linear sRGB” (gamma=1 & sRGB gamut) file in the ACES 1.03 color management.
The code value of this sRGB colorchart photo (de-“camera curve”) is very close to the X-Rite target code value, so I think the right side of the comparison is reliable.
As the waveform monitor shows, the colorspace transformation from “Utility Linear-sRGB” to “ACES CG” to “sRGB(ACES)” ( the darker one) seems not right.
- I found that when ACES shows the log footage on LDR monitor, it always has more contrast and more saturation than traditional color management.
Here is traditional conversion from LogC to Rec709 with 3D LUT in DaVinci Resolve.
Here is ACES color management from IDT LogC to ODT Rec709 in DaVinci Resolve.(more contrast and more saturation than before)
Here is ACES color management from IDT LogC to ODT Rec709 in NUKE (it has the exactly result as it in DaVinci with ACES1.03)
The ACES transformation has beautiful highlight roll-off when handling HDR footage shows on LDR monitor, and preserve the linear code value at the same time. But I’m not sure if the Rec709(or sRGB) look is “correct” , or as the same look on the monitor on-set.