Close a narrow crease from both sides

A fold often has a bright ridge and a dark trough. The detector sees two narrow marks; the eye sees one line. Join both sides with the brush when they separate, because filling only the highlight leaves the shadow as a second crease beside the repair.

The fill advances from the boundary of the marked region and averages intact colour found within reach. That is a strong answer for sky, walls, fabric and gentle tone. It cannot redraw an eye, a letter or the corner of a building when the fold removed those structures.

Eight pixels is the widest neighbourhood available because past that the average stops being local. A larger search may find more source colour, but it also borrows across unrelated edges and produces the soft band restorers call a bruise. If the repaired line is broad and featureless, reduce the reach and repair shorter sections independently.

• A wide torn fold with missing emulsion is outside this local method.
• Repeated texture such as hair, brick and printed lettering needs manual reconstruction or a disclosed generative model.
• Faded colour across the whole print should be corrected after the structural line is closed, not used to hide it.

How wide can the crease be?

The local fill is credible while intact picture remains within roughly eight pixels of both sides at working resolution. Wider folds become missing-picture reconstruction, which this arithmetic pass does not pretend to solve.

Why does the mask miss part of a pale crease?

A low-contrast section may not clear the automatic damage threshold. Paint along the fold with the marking brush so the mask is continuous before filling it.

Should I scan the photograph again from another angle?

Yes when possible. Rotating the print can move the scanner's light relative to a raised fold, turning a bright ridge and dark trough into a flatter signal that is easier to repair.

• Scratches and dustOpens with detection turned up and the brush already out.
• Restore an old photographOpens on fade correction, for a print that has gone pale and warm.
• Scratches, tears and creases are three different problemsOne taxonomy, three fills, one of them built — and what a model does instead.
• RepairImageDetection, an editable mask and the fill, on one column.