NanoAlpha — AI Sprite Transparency Tool

Input images

Light background plate

PNG recommended · same dimensions as dark plate

Dark background plate

PNG recommended · pixel-aligned with light plate

Settings

Light plate color (bgLight)

#ffffff

Dark plate color (bgDark)

#000000

Matting

Alpha cutoff (0–50)

Pixels below this value become fully transparent.

Channel alpha combine Foreground color recovery Foreground guard — min. image diff (%)

Below threshold, pixels stay opaque (helps dark hair & clothing).

Transition width (%)

Difference metric

Noise cleanup

Remove disconnected blobs Keep largest connected blob only Min. blob size (pixels)

Alpha threshold for connectivity

Morphological filter (0 = off)

Erode + dilate before analysis — breaks thin bridges to noise.

Alpha hardening — below becomes 0

Low alpha is invisible on black preview but shows in GIMP/Unity. Try 24–40.

Eyedropper

Pick a target, then click a loaded thumbnail to sample background color.

Preview & export

Try Charmora