Chromatic Aberration PRO

Chromatic aberration is that red-and-blue color fringing around edges - and there are two completely different kinds of it. The subtle one is lateral aberration, where a real lens fails to focus all wavelengths at the edges, and it's so mild you barely notice it (that's Lateral Chromatic Aberration PRO, its own node in this pack). Then there's this one: a uniform, aggressive shift of the color channels across the entire frame. It's what a cheap 90s camcorder lens or a synthetic digital glitch looks like. Chromatic Aberration PRO is that second kind - and it's the rare node in the Post Processing PRO pack that is not subtle.

If the pack's philosophy is "barely perceptible realism," this node is the deliberate exception. You reach for it when you want the image to look broken, not when you want it to look real.

How it works

The mechanism is refreshingly dumb, which is appropriate for the effect. It splits the image into RGB channels and literally shifts the Red channel one direction and the Blue channel the opposite direction, using a circular roll so there are no cut edges. Green stays put. The result is a uniform offset fringe across the whole frame - every edge in the image gets a red glow on one side and a blue glow on the other, like misaligned printing plates.

• shift_x (default 3, −100 to 100) - horizontal shift in pixels. 3 is already clearly visible on a typical render; values in the tens get into full glitch territory.
• shift_y (default 1, −100 to 100) - vertical shift. Defaults small because horizontal fringe is the classic look.

Output is an IMAGE of the same dimensions.

The inputs that matter

Honestly, that's the whole node: image, shift_x, shift_y. Three inputs, one output. The shift_x and shift_y defaults are a good starting "vintage camcorder" amount, but the sweet spot depends on your resolution - a 3px shift at 512px is loud, at 2048px it's barely there, so scale your numbers with your image size.

Installing it

Same pack as everything else - ComfyUI Manager → search "Post Processing PRO", or:

cd ComfyUI/custom_nodes
git clone https://github.com/Guillaume-127/ConfyUI_Post_Processing_PRO

Restart. No requirements file, no model downloads - it's numpy roll operations, instant even on CPU.

Where people get tripped up

The trap is mistaking this node for the realistic one. If you want the photorealistic lens effect - fringing that grows toward the edges while the center stays sharp - this is the wrong tool; that's Lateral Chromatic Aberration PRO, and you want it at tiny dispersion values around 0.003. This node is for stylized lo-fi, glitch, VHS, and horror looks where the fringe is the point. Where it does fit realism-ish work: compositing a "cheap camera footage" layer into a scene that's supposed to look captured on garbage optics. Also worth knowing - the pack's defaults lean subtle everywhere, but here that doesn't apply; the default 3px shift is already visible, so if you genuinely want photorealism, this node is not your friend.