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Activity Forums Blackmagic Design Fusion Fusion Merge node— outputs low saturation

  • Fusion Merge node— outputs low saturation

    Posted by Don Starnes on September 5, 2022 at 6:06 pm

    What is the problem in the attached photo? Why is the output of Merge1 desaturated?

    It’s foreground input, Merge_FG_01, outputs two merged RGBA images as one pre-multiplied image (as a Merge node does). It’s alpha channel is 1.0 for the foreground.

    It’s background input, Magenta, is a Background node set to a solid magenta color.

    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

    Don Starnes replied 1 year, 7 months ago 1 Member · 3 Replies
  • 3 Replies
  • Don Starnes

    September 5, 2022 at 8:32 pm

    Merge1’s foreground input and output have the same waveform and vectorscope images (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.

  • Don Starnes

    September 5, 2022 at 9:17 pm

    Attachment: Merge1’s foreground input and output have the same waveform and vectorscope images

  • Don Starnes

    September 6, 2022 at 4:07 am


    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.

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