Lateral Chromatic Aberration PRO

Real lenses are imperfect in a specific, mathematical way: they can't bend every color of light to exactly the same point, so at the edges of the frame you get faint red and blue fringing that grows with distance from the center - while the middle of the image stays perfectly sharp. That's lateral chromatic aberration, and it's one of the most reliable "this was shot through glass" tells in real photography. AI models almost never generate it, which is precisely why adding it in post makes renders feel more like photographs. Lateral Chromatic Aberration PRO is the pack's faithful version of that real-lens effect.

The name matters: this is the physically accurate sibling of Chromatic Aberration PRO, the pack's aggressive global-shift node. Same family of artifact, opposite intent. This one is for realism; the other is for glitch aesthetics.

How it works

The node computes, for every pixel, its normalized squared distance from the frame center. Red and blue channels are then radially displaced by a factor that scales with that distance - red_dispersion positive pushes red outward, blue_dispersion negative pulls blue inward (the defaults point them in opposite directions, which is how a real lens fringes). Green is left completely untouched as the "in-focus" reference, and each displaced channel is remapped with high-quality Lanczos interpolation plus reflect-edge padding so nothing tears at the borders.

The physics framing is real: this is the standard 1 + k·r² radial model used for lens aberration correction in optics software - here inverted to add the aberration instead of removing it.

The inputs that matter

• image - your IMAGE tensor.
• red_dispersion (default 0.003, range ±0.05) - how far red fringes outward.
• blue_dispersion (default −0.003, range ±0.05) - how far blue fringes the other way.

The range is small because the effect is small. At the defaults you get a whisper of fringe at the corners; bump to 0.01 and it becomes clearly visible on high-contrast edges. Output is a single IMAGE of the same size.

Installing it

One of 14 nodes in the Post Processing PRO pack. 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 - numpy grid math plus OpenCV remap, runs on CPU fine.

Where people get tripped up

The classic mistake is cranking the sliders because "nothing's happening." At the 0.003 default, the fringe is genuinely subtle - that's the intent. Zoom into a corner where a bright object sits against a dark background and you'll see it. If you want it loud, you've grabbed the wrong node; that's Chromatic Aberration PRO. The other gotcha: this only fringes edges, never the center, so if you're compositing AI content onto real footage, match the amount to the real lens - real lenses fringe more at wide angles and fast apertures. And as with all the pack's optics, it layers nicely with Lens Distortion PRO: distortion breaks the perfect geometry, lateral CA adds the color fringe, and together a render starts to feel like it came out of an actual camera.