Hello, I am having an issue with my PA32UCDM calibration setup. When measuring a white patch through ColourSpace server via DaVinci Resolve, I get between 998-1000 nits. However, when I display an identical 3% white patch directly from DaVinci Resolve, I measure 1025-1030 nits.

My settings are Patch Scale Full, Resolution 8-bit, Data Levels in Resolve Full, same 3% patch size in both cases, HDR P3-D65 PQ calibration, signal path DaVinci Resolve through Decklink Mini Monitor 4K HDMI to PA32UCDM.

The 20-30 nit difference concerns me because after calibration brightness drops another 30-40 nits, meaning I am losing significant peak brightness. Does ColourSpace through Resolve inherently send a lower brightness signal than a native Resolve patch? Is this affecting calibration accuracy?

Thank you in advance.

If there is a difference in the measured value then the patch being displayed is different.
You will need to define what is causing that difference.
Are you sure the patch sizes are totally identical for example?

All ColourSpace does is sent a triplet value to Resolve to be displayed.
If that is somehow being displayed incorrectly, likely do to some setting within Resolve, then there will be a difference.
Try a different TPG too.

Steve

Place markers on your monitor, such as a piece of paper or blue painter's tape, to verify that the displayed patches are the same size.