Image Channel Select

Stereo content loves to travel as a side-by-side (SBS) or over-under image: one frame, two eyes, glued together along the middle. Before you can do anything useful with it - feed one eye to a depth or disparity pass, process each half separately - you have to split it. That's this node's entire job, and it does it cleanly.

Feed in an image and pick a channel:

• Left or Right - takes the corresponding half of a side-by-side frame.
• Top or Bottom - same idea for over-under layouts.
• Left:Right - splits a SBS frame and stacks the two halves into a 2-frame batch. Same resolution, batch of 2. Handy when your next node wants frames rather than one wide image.
• Top:Bottom - the over-under version of the same trick.
• RGB - passes the image through untouched, so the node can also sit in front of normal flat frames without complaining.

The output is an IMAGE, at whatever half-resolution (or batch) your choice implies. That's the whole node, and it's better for being exactly that.

Why you'd reach for it: pulling one eye out of a stereo capture is step one for any disparity work - disparity is literally "how much the two eyes differ," and you need the eyes separate to compute it. The batch-stacking options are the sleeper feature: turning a SBS frame into two proper frames in one step is the kind of plumbing that usually takes three nodes.

Two gotchas. First, the split uses floor division, so an odd-width image gives you two unequal halves that don't add back up - keep your stereo frames even. Second, Left:Right does not produce a narrower image; it doubles the batch. That trips people up every time; they expect a half-width result and get two full-width frames. And if you're after channel extraction (Red/Green/Blue/Alpha) rather than spatial halves, this pack's MaskChannelSelect is the sibling for that.

It ships in andygill's comfyui-sunflower-nodes, a tiny 3D-visualization pack with no models and no heavy dependencies. Install via ComfyUI Manager (search comfyui-sunflower-nodes) and restart, or:

cd ComfyUI/custom_nodes
git clone https://github.com/andygill/comfyui-sunflower-nodes

Then restart ComfyUI. One heads-up: the repo has been quiet since spring 2025 and is currently unreachable on GitHub, so if the clone 404s, an archived copy of the code installs the same way.