Which repair tool removes what

If you take nothing else: reach for spot heal first because it is one click, and escalate only when it fails. Most people reach for AI first, wait for a model to download, and use a cannon on a dust speck.

Spot healing throws away everything inside your brush and rebuilds it from the boundary inward. It works outward-in: the pixels nearest known good data are filled first, then the next ring, and so on to the middle. Because information travels inward from the edge, an edge running underneath the mark gets carried across it rather than averaged away.

That inward propagation is why it is not simply a blur, and why it can bridge a thin line — a phone cable across a sky, a scratch across a face — that a smoothing tool would just smear.

Both ask you to sample a source point and then paint. What happens next is completely different, and it is the most useful distinction in retouching.

Clone copies the pixels. Whatever you sampled arrives exactly as it was — including its brightness. Sample from a lit area, paint into a shadow, and you get a bright patch sitting in a shadow with a hard rim around it. That is not a bug; it is the tool being literal, and literal is what you want when you are continuing a brick course or a handrail.

Heal copies the differences between pixels — the texture — and then solves for a set of values that has that texture and also matches the destination exactly at the edges of your stroke. Sample from the lit area, paint into the shadow, and the pores and grain come across while the tone stays shadow-dark. No rim, because the maths is pinned to the surroundings.

• Choose heal when the texture is what you need and the lighting differs.
• Choose clone when the shape is what you need and it must be exact.
• Heal on a hard edge smears, because it is solving for smoothness across your stroke. Clone across a lighting change seams, because it is not solving for anything.

The three tools above all move existing pixels around. None of them can invent something that is not somewhere in the photo already. Remove a person standing in front of a hedge and you can heal the hedge back, because there is hedge either side. Remove a person standing in front of a doorway, and no amount of sampling will produce the door frame that was behind them, because it was never photographed.

That is the line. Ask yourself: is what belongs here visible somewhere else in this photo? If yes, one of the brushes will do it faster and more convincingly. If no, you need a model that will make something up.

• Cover the whole object, including its shadow and any reflection. A mask that stops at the edge leaves that edge as context, and the model will helpfully paint more of the object back.
• Go slightly wider than you think. Models handle a generous margin better than a tight one.
• Remove one object at a time. Two marks in one pass gives the model less surrounding context for each.

The blur tool is worth understanding precisely because it is not a repair tool. It never samples, copies or invents anything — every value it writes is an average of what was already under the brush. Blurring a licence plate leaves a licence plate; it is just unreadable.

That distinction matters when you are obscuring something for a real reason. Blur is reversible in principle and, on small text, sometimes in practice. If someone must not be able to recover what was there, remove it — do not soften it.