Orion4D · Channel Mixer APP

Most people convert to black and white by desaturating and call it a day. Then they wonder why the result is flat. Orion4D_FXMax_ChannelMixer (displayed "Orion4D · Channel Mixer APP") is the reason their conversions are flat: real black-and-white is about mixing channels, not discarding color. It's the same tool Ansel Adams-era photographers used with colored filters on the lens, now as a node.

How it works

A channel mixer lets you build each output channel (Red, Green, or Blue) out of percentages of the input channels plus a constant. So the output Red channel might be 70% input red, 30% input green - you're remixing the image's color information, not just averaging it. The settings: red_source, green_source, blue_source percentages (each −200 to +200), a constant, and two crucial toggles - monochrome and preserve_luminosity.

The magic is in the presets. Mono Red Luma is the classic: it drives a monochrome conversion using a red-weighted luminance mix, which darkens blue skies and brightens skin the way a red filter on a camera did - giving that contrasty, "proper" black-and-white look that grayscale never achieves. This is the preset worth loading just to see the difference.

Inputs and outputs

Pack-standard schema:

• image - the IMAGE tensor.
• preset - Neutral (identity) or Mono Red Luma.
• raw_settings - "Embedded JSON settings used for workflow portability. Managed automatically by the APP."
• mask (optional) - mix only part of the frame.

Outputs: image and mask.

Where it fits

Two use cases. First, serious black-and-white: enable monochrome, dial the channel percentages, get a conversion with actual depth. Second, creative color: without monochrome, you can swap channels around entirely for that color-shifted, infrared-photography vibe or stylized looks that HSL can't produce because it only rotates within the color wheel. The matrix math is the same family as the pack's Matrix 3x3 node - Channel Mixer is just the curated, per-channel way of doing it.

Performance and install

A CPU/NumPy node - the README slots it in the moderate tier: barely noticeable on single images, a slight delay on video batches. Install is the pack standard:

cd ComfyUI/custom_nodes
git clone https://github.com/orion4d/Orion4D_FXMax.git
# restart ComfyUI

ComfyUI Manager search "Orion4D_FXMax" also installs it. No models, Pillow-only.

Gotchas

Percentages can overshoot: if your sources don't roughly sum toward 100%, you'll clip highlights or crush blacks, and that's what the clamp behavior and preserve_luminosity toggle exist to protect against. For monochrome work, keep preserve_luminosity on or the brightness will jump around as you mix. And save your mixes - the "New Preset" flow exists so you don't rebuild your favorite B&W recipe every time.