[Kritsada Kaewmani]

Thank you for reply
It’s been one year 🙂 I did some test ands found out pros/cons of grading in ACES color space on Resolve.
Conversion from other color spaces to/frome ACES is easy as far as we know the chromaticities of them. Unfortunatly grading in ACES on Resolve is not easy. It’s all about the work flow. For example if I finish a shot and render out into Rec709 I will not be able to put some of superimposed text or VFX elements and replace it into the original ACES timeline for re-grade. I have to render out to ACES but this creat anoter problem, many VFX artists did thier job in sRGB so i have to convert VFX elements into ACES. I tried to simplify this by using LUTs in the Resolve timeline but applying LUTs in the ACES mode is not the way to go. ACES is HDR and wide gamut but 3DLUTs are only 17,33 or 64 steps. Applying series of 3DLUTs can causes some artefacts. To meet flexibility and deadline i gave up using ACES for now.

[Kritsada Kaewmani]

sRGB and Rec.709 share the same color primaries.

R x=0.64 y=0.33
G x=0.30 y=0.60
B x=0.15 y=0.06

with D65 White Point
x=0.3127 y=0.3290

That’s why many people use sRGB and Rec.709 interchangeably.
BUT gamma curve of sRGB and Rec.709 are really different.

“Rec.709 gamma curve” is only used in Camera.
“sRGB gamma curve” is for monitor.

If your monitor’s gamma curve is sRGB the DPX rendered out from Resolve will be sRGB not Rec.709.

[Kritsada Kaewmani]

4270_canonclog.zip

Check out this link if somebody want to try *.ilut version of all original *.csv format.

[Kritsada Kaewmani]

Oops i forget one thing. I use plain Rec709 curve for output LUT.

[Kritsada Kaewmani]

It should not be converted to 3D LUT cube because the original *.csv curve is 10bits 1D LUT.
3D LUTs have much less steps than 1D LUTs, for this case making a Resolve’s *.olut (output 1D LUT) is the best way to go.

I have *.olut versions of all original *.csv versions supplied by Canon.
–CanonLog10ToCineon10LUT_ver1.0.csv
–CanonLog10ToRec709_ver1.0.csv
–CanonLog10ToVideo_ver1.0.csv

However,

-I don’t use CanonLog10ToCineon10LUT_ver1.0.csv because i don’t know when to use it.

-The CanonLog10ToRec709_ver1.0.csv simply cut everything above 648 [of 0-1023] it’s for someone who want to change the CLog images to Rec709 with hard clipping.

-The CanonLog10ToVideo_ver1.0.csv is the soft rollout version of The CanonLog10ToRec709_ver1.0.csv it’s for someone who are not pleased by hard clipping Video look.

I find myself not to use one of them because after i converted from C-Log to Rec709(or Video) the DR is compressed, the tonal curve is no longer linear light, a bit harder to grade. I think those curve are for simple CLog-Video conversion such as transcoding original MXF to QuickTime for editorial not for color correction in postproduction. I’m searching for a white paper of Canon-Log ( like ARRI made one for AlexaLogC ) but i can’t find it. Now i simply grade on Canon Log directly. The first node is Primary decrease the gamma, increase the gain and apply some soft clip if you like. The next nodes are series of Primaries/Secondaries. By this way i will get what i want easier.

[Kritsada Kaewmani]

I assume that they shoot RED vs ARRI on different scenes so you can’t see the difference of the easy setup. But If it’s the same scene you may need to select “Camera RGB” and “Custom PD Log” then fine tune Black point, White point and Film gamma of the RED shot againts ARRI shot to minimize the difference.

[Kritsada Kaewmani]

The easiest way to make R3D files reasonably close to AlexaLogC (without dealing with complicated color science) is setting R3D file color space to “CameraRGB” and gamma curve “RedLogFilm”. Then follow AlexaLogC workflow.

[Kritsada Kaewmani]

I think the ACES/IIF is not new it has been used by people in need of HDR and Wide Gamut color space for a while.
RED CINE-X can transcode r3d files into OpenEXR format with the ACES color space option.
Many of VFX/Composite softwares support OpenEXR and ACES.
Resolve(TM) just added new color science named “DaVinci ACES” I wish i could have more information about it.
I want to know more about IDT/ODT where are they in the Resolve directories and how it looks like then i can modifiy them or make a new one. Unfortunately there are only few documents about Davinci ACES.

Bangkok, Thailand

[Kritsada Kaewmani]

Finally, i figured out that there are 2 types of ADX encoding, ADX10 and ADX16.
ADX10 is nearly the same as the DPX 10 bits log density range=2.046.
ADX16 has density range=8.191875 ( 4 times of ADX10 ).

The ADX LUTs in Resolve both IDT and ODT are ADX16.
I really hope that there will be ADX10 in the next version.

Thanks

Bangkok, Thailand

[Kritsada Kaewmani]

I did many comparision of the same file with/without Red Rocket at 4K. The sharpness is somewhat different and show more datails in the dark area with deeper black.