Stable Manifold Low / High Split

The whole Stable Manifold trick rests on one assumption: your high-res FLUX.2 (especially Klein) image has a low-frequency "stable" core - composition, lighting, color - that drifted as resolution rose, sitting underneath a high-frequency layer of detail that's actually fine. StableManifoldLowHighSplit is the node that shows you those two layers, separated. It's the diagnostic sibling in the pack's affine path: you reach for it when you want to see what the correction is about to preserve before you run it, not after.

Mechanically it's embarrassingly simple, and that's a feature. The input image gets a Gaussian blur with radius sigma, and that smoothed version is the low output - the structure band. The high output is the original minus the blurred version: the detail residual. No neural network, no warp, no model download; it's a few lines of pure tensor math that runs in seconds.

The one knob that matters is sigma (default 8, range 0–64). It's the cutoff: bigger sigma pushes more into low (coarser structure) and more into high. Tune it to match what you actually consider "stable" in the image. If your drift shows up as whole-scene relighting, that lives in the low band; if it's texture or grain, it's in the high band.

Where it fits: pair it with StableManifoldRecombine, its exact inverse, in the affine/diagnostic workflow. Split → eyeball both bands → decide whether your profile should be fighting geometry or chroma → recombine. It's also a perfectly good standalone inspection utility on any image, even outside this pack's main path.

Installing

ComfyUI Manager is the easy route - search "ComfyUI-StableManifoldCompander" in the Custom Nodes Manager and hit install. Or the manual way:

cd ComfyUI/custom_nodes
git clone https://github.com/xmarre/ComfyUI-StableManifoldCompander

Then restart ComfyUI. Keep the default folder name - the README shows a hyphenated variant, but the module path expects ComfyUI-StableManifoldCompander. No model files, no extra Python dependencies (requirements.txt is literally "No additional required dependencies"). It's pure image-space math on tensors you already have, so it's light. The only pack node with an extra dependency is the detailer hook, which wants Impact Pack.

Gotchas

Two honest notes. First, the high output is a residual centered near zero, so it can look flat and gray in the preview. That's not corruption - it's what a detail band looks like; recombining it at strength 1 reconstructs the original cleanly. Second, if you crank sigma past maybe 40–50, you're basically just looking at a blurry poster of your image and the split stops telling you anything useful.

This is a small, early pack - zero community chatter to lean on, so treat defaults as a starting point - but this particular node is so simple that there's little to get wrong.