RC Outer Glow

Neon text, glowing buttons, a logo that looks backlit - these are "layer effects" in Photoshop, and in ComfyUI they're usually a painful little construction site of blur, composite, and blend nodes held together with bad luck. RC_OuterGlow is this pack's version of Photoshop's Outer Glow layer style, and it does the whole thing in one node: take the image's alpha, grow it into a soft colored halo, blend it behind the original, and - the nice part - expand the canvas so the glow doesn't get chopped off at the edges.

It lives in the RC Image Compositor pack under RC/Layer Effects, alongside Drop Shadow and Stroke. If you're building UI mockups, title cards, or watermark workflows, this is one of the three nodes that make the pack worth installing.

How it works

The mechanism is straight out of a Photoshop layer-style playbook: it reads the alpha as a mask, dilates it by the spread amount, blurs it by the size amount, tints it with the glow color, and composites it under the original using a blend mode. The controls map cleanly:

• size (0–100 px) - the blur spread of the glow itself.
• spread (0–100) - a "choke" that thickens the glow's core before blurring. More spread = denser, tighter glow.
• color_r / color_g / color_b - the glow color, RGB 0–255. Default is yellow.
• opacity (0–1) - glow strength.
• blend_mode - screen (the classic glow), plus normal, color_dodge (intense), linear_dodge (soft), and lighten (gentle).
• fill_opacity - this one's fun: it controls the original image's opacity. 1.0 = normal image with glow; 0.0 = hollow, glow-only outline; 0.5 = ghosted image plus glow.
• auto_expand_canvas (default on) - grows the output canvas by roughly size*4 + spread*2 so the halo isn't clipped.

Output is a single IMAGE - and note it may be larger than the input when auto-expand is on.

Installing it

ComfyUI Manager → search "RC Image Compositor" → install, restart. Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/kj863257/ComfyUI_RC_Image_Compositor
cd ComfyUI_RC_Image_Compositor
pip install -r requirements.txt

Dependencies: pillow, numpy, opencv-python. Nothing to download.

Where people get burned

• Auto-expand changes the output size. If your workflow assumed a fixed canvas and a glowing logo comes out of this node 40px bigger on every side, that's not a bug - the canvas grew to fit the glow. Compose the result after this node, or turn auto-expand off and accept clipping.
• fill_opacity 0 is a hollow effect, not invisible. It's the "glow only" look - the image disappears and the halo becomes the outline. If your text vanished, that's the slider.
• Glow quality is capped by the input's own alpha. A blurry, jagged cutout produces a blurry, jagged glow. Feather or clean the alpha upstream (the pack's MaskApply feather helps) before expecting a polished halo.
• screen on a dark background is where glow reads best. On a white background, screen has almost nothing to add - switch to normal or lighten and compensate with opacity.

If you've been stringing together blur+blend nodes to fake a glow, this collapses the whole construction site into one node with Photoshop-familiar knobs. That's the pack's whole thesis, and Outer Glow is one of its best arguments.