Fusion Merge node— outputs low saturation [solved]


The output of my Merge node (Merge1) has low color saturation. Why?

Its background input is a Background node set to a solid magenta color.
Its foreground input is from the output of another merge node (two merged RGBA images as one pre-multiplied image— as a Merge node does). It’s alpha channel is 1.0 for the foreground.

Merge1’s Channels and Settings tabs use default settings.

The same thing happens when I input media (H.264 video) as a background in Merge1.

Just for grins, because this looks a bit like an alpha multiplication issue, I tried setting Merge1 to Subtractive and even tried Alpha Multiply and Alpha Divide nodes before Merge1 on both inputs: didn’t help.

What am I doing wrong?

Fusion in DaVinci Resolve Studio 18
Mac Mini (M1, 2020), 16Gb
MacOS 12


Merge1’s foreground input and output have the same waveform and vectorscope values (the same brightness and saturation).
Switching the viewers of each merge node doesn’t change its image (the Viewers LUTs match).

I can sort of match the input and output in the Viewer with a Color Corrector node before Merge1– while distorting Merge1’s output signal, with a wildly different waveform and vectorscope image from its foreground input.


This is an artifact of the Fusion clip being inside a timeline inside of a compound clip in DaVinci Resolve. When I back out of the Fusion page and look at the image in the timeline, the saturation, etc., is correct.

This is odd, and surely a bug. This means that, in this arrangement, I can’t comp and see the image from this Merge node correctly in a Viewer at the same time. But: at least I can use the comp.

This Russian doll approach is my attempt to edit in a low resolution timeline and composite in full resolution. Fusion inputs stacked clips at the timeline resolution. To overcome this limitation, I edit each VFX sequence in a full resolution timeline inside a compound clip.

If you know of a better method for editing at low resolution and comping at high resolution, I’d love to know it!

I expect that Blackmagic Design will iron all of this out as it continues to better integrate Fusion into Resolve.