Inpainting: Fixing One Part of an Image

Inpainting is repair work. You have an image that is ninety per cent right and one region that is wrong — a hand with too many fingers, an object nobody asked for, a patch of background that went to mush — and you want that region redone without touching anything else. It is the most surgical thing you can do to a generated image, and it fails in ways that have almost nothing to do with your wording.

The Mask Does Most of the Work

Before the prompt matters at all, the shape of the selection matters. A mask drawn tightly around the defect gives the model almost no room to work with, and the new content gets crushed into the outline you drew — this is why a tight mask around a bad hand so often returns another bad hand in exactly the same silhouette.

Include context. Mask the hand and some of the forearm and some of the surrounding background, so there is space to place the fingers somewhere new. Feather the edge if the tool allows it, because a hard boundary produces a visible seam even when the content inside it is perfect.

The opposite mistake is masking too much. Select half the picture and you are no longer repairing anything, you are re-generating with a partial reference, and elements you were happy with will come back altered.

Describe the Patch, Not the Picture

Inpainting prompts should describe what belongs in the masked region, in context, and nothing else. If you are replacing a chair, the prompt is a short description of the chair you want plus enough of the surroundings to place it — the wooden floor it stands on, the light falling from the left. It is not the description of the whole scene, which pulls the patch toward being a small complete image of its own rather than part of a larger one.

Removal is worth stating positively. Asking for something to be gone tends to work less well than describing what should be there instead: not “remove the sign”, but “plain brick wall continuing across”. The model is filling a hole, and it does that better when it has been told what the hole contains.

When the Patch Will Not Blend

The most common complaint is a repair that is technically correct and still obviously a repair — slightly different light, slightly different grain, slightly cleaner than everything around it. Naming the lighting direction and the medium in the inpainting prompt usually closes most of the gap, since the model has no view of your original prompt and no reason to match its treatment otherwise.

If it still reads as a patch, widen the mask so the boundary falls somewhere visually quiet — flat wall, open sky — rather than across a face or a strong edge, where the eye goes looking for discontinuity. And accept multiple passes as normal. Inpainting a complicated fix in one attempt is unusual; a hand repaired in three narrowing rounds is how it typically goes.