〽️ Image Ops Channel

ImageOps Channels is the node you reach for when you want one channel of an image as its own grayscale plate. Pick Red, Green, Blue, or Alpha, and it hands you that channel as an image plus the equivalent mask. It's not a flashy node - it's a utility, the kind of thing compositors reach for constantly and plain ComfyUI makes oddly awkward. It's part of the ComfyUI-Majoor-ImageOps pack, where it inherits the pack's batch-first behavior: feed it a stack of frames and it extracts the channel from every frame.

What it's for

Where does extracting a channel actually matter in a ComfyUI workflow?

• Masks from colour. A green screen plate where the green channel carries most of the signal, or a UI screenshot where the red channel is cleaner than the full-color image - extract the channel, then run it through Mask Convert or use it as-is.
• Alpha extraction. The alpha option pulls the transparency channel out of an RGBA image as a standalone mask. That's the move when you need the matte of a PNG (say, an ICLight or transparent output) to drive something downstream.
• Debugging. Red channel looks different from the full image? Sometimes channel inspection shows you exactly where a bake or a tint went wrong.

The image output is the single channel promoted back to a grayscale-looking RGB image (black-and-white), and the mask output is that same data as a [B, H, W] mask - so you can wire whichever type the next node expects. There's no mask input on this one and no invert_mask; it's deliberately a one-trick node, and the trick is clean.

The input that matters

Just channel - a dropdown with Red, Green, Blue, Alpha - plus bypass to pass the input through unchanged. The image input accepts standard IMAGE batches and VIDEO frame sources from packs like VHS, which is the same input contract every node in this pack shares.

Install

ComfyUI Manager (search "ComfyUI-Majoor-ImageOps"), or:

cd ComfyUI/custom_nodes
git clone https://github.com/MajoorWaldi/ComfyUI-Majoor-ImageOps

Restart and hard-refresh the browser (Ctrl+F5 / Cmd+Shift+R). No models, no extra dependencies.

The thing people miss

For RGB images the Alpha option just returns a fully-opaque white plate - alpha doesn't exist until the image actually has a fourth channel. If you extract Alpha and get white, that's not a bug; your source simply has no transparency. Feed it an RGBA image and suddenly the alpha channel appears as a real shape. That one behavior confuses people more than anything else in this node, so now you won't be one of them.