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Avoiding gamma shift when exporting from Resolve 17.2

When you export a video file from a Rec.709 2.4 gamma project in DaVinci Resolve 17.2, the film may look darker than the original in QuickTime player on macs and some other video players/web services.

The video file will look the same as the original in Resolve, but QuickTime player does not recognize the 2.4 gamma tag and the video will look darker. The fix is to use the same gamma tag as the original: Rec. 709-A when exporting from Resolve.

If you have Project setting – Color management with Rec.709-A Timeline Color space you will get the same gamma tag as the original video file.

If you have Project setting – Color management with Rec.709 Gamma 2.4 Timeline Color space you will get the unrecognized gamma tag. Sometimes it is important to have the Timeline Color space as REC.709 Gamma 2.4. One example is when you drop a DCP in the timeline and the DCP is converted from DCI X’Y’Z’ to the timeline color space. Then the solution is to change the tag when exporting.

How to fix the gamma tag when exporting

The default in Advanced Settings when exporting is:
Color Space Tag: Same as Project
Gamma Tag: Same as Project

The original QuickTime from Final Cut X had these tags:
Color Primaries: ITU-R BT.709
Transfer Function: ITU-R BT.709
YCBCr Matrix: ITU-R BT.709
Code Points: (1-1-1)

The Quicktime with the Rec 709, 2.4 gamma tag was recognized in QuickTime player as:
Color Primaries: ITU-R BT.709
Transfer Function: Unspecified
YCBCr Matrix: ITU-R BT.709
Code Points: (1-2-1)

Choose Rec-709-A as the gamma tag

If you want to avoid gamma shift in QuickTime player you have to choose Rec.709-A as the Gamma tag when exporting.

When exporting choose

In Advanced Settings:

Color Space Tag Rec.709
Gamma Tag Rec.709-A

Now the Quicktime has the same tags as the original and does not have a gamma shift in Quicktime player.
Color Primaries: ITU-R BT.709
Transfer Function: ITU-R BT.709
YCBCr Matrix: ITU-R BT.709
Code Points: (1-1-1)

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