Merge RGB

The companion node to Split RGB - it takes three images and stacks them into one, treating each input as if it were a single color channel. Its obvious job is putting a split-apart image back together after you've done something to one of the channels in between. Its less obvious job, which the pack's own author calls out directly, is that there's nothing stopping you from feeding it three completely unrelated images "for trippy effects" - since it doesn't check that its inputs came from the same source, only that it uses each one's channel data.

How it works

For each of the three inputs, the node extracts only the channel matching that input's slot - the red input contributes its red channel, green contributes its green channel, blue contributes its blue channel - and stacks those three channels into one new RGB image. If you feed it the genuine outputs of Split RGB, you get your original image back unchanged. Feed it three unrelated photos instead, and you get a chromatic-aberration-style mashup where each channel carries a different image's structure.

The inputs and outputs that matter

• red - image whose red channel becomes the output's red channel.
• green - image whose green channel becomes the output's green channel.
• blue - image whose blue channel becomes the output's blue channel.

That's the entire node - no sliders, no options. Output is a single IMAGE.

How to install it

ComfyUI Manager: search Virtuoso Nodes for ComfyUI, install, restart. By hand:

cd ComfyUI/custom_nodes
git clone https://github.com/chrisfreilich/virtuoso-nodes
pip install -r virtuoso-nodes/requirements.txt

Restart, find it under Virtuoso/Channels. No model downloads, negligible compute.

Common issues & troubleshooting

Recombined image doesn't match the original. If you edited one of the three channel images (say, ran Levels on just the red channel from Split RGB) before merging, that's expected - the whole point is the edit shows up only in that channel. If you didn't edit anything and it still looks off, double check each input went into the matching slot - swapping, say, the green and blue images into the wrong inputs produces a subtle but real color shift.

Want more control during recombination than a straight channel stack. The pack's own README suggests an alternative: run Blend Modes with linear dodge (add) twice instead of using this node, which accomplishes the same recombination but lets you set independent opacity per channel along the way - useful if you want to grade the channels relative to each other during the merge rather than after.

Trying to isolate or recolor a specific hue, not literal channels. Merge RGB works on raw red/green/blue channel data, not color ranges - if what you actually need is targeting "the blues" or "the reds" as a color selection, that's Selective Color or Hue/Saturation, not this node.