NSS BG

Core Tools

Edge refinement

Feather, smooth, expand, and decontaminate edges to get natural-looking cutouts.

Overview

Edge Refinement is a set of non-destructive adjustments that sit on top of the AI mask. They let you fix systematic edge problems without painting pixel-by-pixel with the brush. Use them for:

  • Softening hard, mechanical-looking edges (Feather)
  • Smoothing jagged or noisy edges (Smooth)
  • Pulling the mask in or pushing it out (Contract/Expand)
  • Removing colour spill from the original background (Decontaminate)

Feather

Range: 0–20 px

Applies a Gaussian blur to the mask boundary, creating a soft, gradual transition from opaque to transparent. Mimics the natural falloff of out-of-focus edges.

  • 0 — no feathering, sharp edge
  • 5–10 — subtle softness, good for most photos
  • 15–20 — pronounced softness, useful for wispy hair or motion blur

When to use: Subject looks "cut out" with a hard, plastic-looking edge. Hair, fur, or fabric looks too crisp.

Smooth

Range: 0–10

Applies a morphological smooth to reduce jagged or noisy pixels along the edge. Higher values produce rounder, more continuous contours.

  • 0 — no smoothing
  • 3–5 — moderate, removes most noise without losing detail
  • 8–10 — aggressive, simplifies complex edges significantly

When to use: Edge looks choppy or pixelated at 100% zoom. The subject has a naturally smooth silhouette but the mask is jagged.

Contract / Expand

Range: -20 px to +20 px

  • Negative values (Contract): Erodes the mask inward, removing a thin layer of background pixels that snuck into the cutout. Useful when you can see remnants of the original background colour along the edge.
  • Positive values (Expand): Dilates the mask outward, capturing more of the subject. Useful when the AI has clipped hair tips or fine details.

When to use: Contract when there's a visible colour fringe. Expand when hair ends or fine details are being cut off.

Decontaminate

Default: On (50% strength)

Range: 0–100%

Removes background colour spill from semi-transparent edge pixels. When a subject is photographed in front of a coloured background, that colour partially bleeds into the edge pixels — especially with hair and fur.

Decontaminate works in Lab colour space to push edge pixel colours toward the pure foreground colours, scaled by how transparent the pixel is.

  • 0% — off
  • 50% — default, removes most visible spill without affecting opaque areas
  • 100% — maximum removal, aggressive on heavy spill but may shift natural tones slightly

When to use: You can see a green/blue/red tint along the edges that wasn't in the original subject. Especially common with product photos on coloured backgrounds.

Preserve soft edges

Default: On

When on, the mask retains sub-pixel alpha values — semi-transparent pixels for smooth transitions.

When off, the mask is thresholded to binary (fully opaque or fully transparent). Use this for icons or logos where you want perfectly sharp, aliased edges with no partial pixels.

Caution: Turning this off permanently discards soft-edge data. You'll need to toggle it back on and re-apply to recover them.

Order of operations

Edge Refinement adjustments apply in this order:

  1. AI mask (base)
  2. Decontaminate
  3. Contract/Expand
  4. Smooth
  5. Feather

Adjust them in any order you like — the result is always recomputed from the base mask.

Related

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