Why edges make or break a cutout
A binary mask draws a hard line: pixel in, pixel out. Real photographs don't work that way — a strand of hair might cover 30% of a pixel, and a hard mask has to lie about it. Alpha matting stores that 30% as partial opacity, which is why matted cutouts sit convincingly on both light and dark backgrounds while hard-masked ones show a telltale fringe.
The hardest cases are edges that share color with the background (dark hair on a dark room) and translucent materials like glass or veils. If you're generating the source image yourself, you can dodge all of this: prompt for tonal separation between subject and backdrop and the matte comes out near-perfect.
Tips for production-grade cutouts
Work at the highest resolution you have — edge quality is resolution-bound, and a matte pulled from a large image survives downstream scaling far better than one pulled small and enlarged. If your source is small, upscale first, then remove the background.
After cutting, audit the edge at 200% zoom against both a white and a black canvas; each reveals a different kind of fringe. If the subject is going onto a scene with different lighting, run Nidhogg's relight pass on the cutout so the light direction and color temperature match the destination — that's the step most composites skip and the reason they look pasted.
Everyday jobs it unlocks
E-commerce is the volume use case: shoot or generate a product once, cut it out, and place it on pure white for the catalog, lifestyle scenes for ads, and seasonal backdrops for campaigns — one asset, many contexts. Marketplaces that mandate white backgrounds make this a compliance step, not just a style choice.
Creators use it for thumbnail subjects that pop off the frame, sticker packs, profile pictures, and slide decks. Designers use it as the first step of any composite: subject out, new world in.