When the grouping is wrong
The scan is a grouping, not a verdict, and it is wrong now and then: two look-alike children in one circle, a face of Maya's filed under nobody, a plush toy drawn as a person. This page covers the three corrections, each made from a right-click menu and written to the library the moment you choose it, so scanning new photographs does not undo it, and none of them changes a decision, a rating or a label on any frame.
Two people in one circle — Not Maya
The frame's own menu is on the Frames view (G from Single). Right-click a frame on the sheet and the menu lists each person the scan found in it: Not Maya for a named person, Not this person (12 frames) for an unnamed one. When none of the people drawn as circles is in the frame, the menu reads No one recognised in this frame instead. That includes a frame whose only face is someone seen once, and on such a frame the menu can still offer This is Maya under a divider (below).
Choose Not Maya and that frame's face leaves her, and scanning new photographs does not put it back. The frame leaves her pass if she is selected, and her count drops by one — unless the frame is rejected, since her count never includes rejected frames. The face taken away is grouped again with all the others: it forms a circle with other faces that look like it, joins another circle, or stays on its own, counted in the faces seen once line under the circles. A face under about a fortieth of the frame's width can also be grouped with other faces that small. Such a group gets no circle until a larger face of that person turns up, and it is not in the faces seen once line either, so those faces can stay out of sight in the People section. Her picture is chosen again from the faces she has left, so the face you took away is never her picture.
To split two look-alikes filed as one: click All frames at the top of the Groups pane, which puts every chip down and sets All (an open proposal pass keeps its own chip, so put that down too). Then click the circle, so the pass is all their frames, switch to Frames (G from Single), and on each frame of the second child choose Not Maya. Their faces can then form a circle of their own. They do when at least two of them look alike and one is large enough to read, about a fortieth of the frame's width. If not, they join another circle, are counted among the faces seen once or, when they look alike and every one is smaller than that, wait out of sight as described above.
A face the scan missed — This is Maya
Right-click a frame in Frames that holds a face of Maya's that sits under no circle, or under the wrong one. After a divider — under the Not … items, or under No one recognised in this frame — the menu offers This is Maya for each named person who is not already in the frame and who is drawn as a circle in the People section. A named person who has no circle, with a single face left after a correction, say, is not offered, and nobody is offered unless the scan found a face in that frame to pin.
Choose it and the largest face in the frame that is not already hers is pinned to her, whoever that face is filed under now: a stranger, or another named person. The pin outlasts every scan of new photographs, and it outranks a name, so a face pinned to Maya leaves the person it was in. An earlier Not Maya on that face is withdrawn.
This is Maya takes the largest face that is not already hers, and it cannot be pointed at another. Take a frame where Leo's face is larger than Maya's and Maya's sits under no circle: the menu offers Not Leo and This is Maya, and This is Maya moves Leo's face to her. Look at the frame before you choose.
If the wrong face was pinned, choose Not Maya on the same frame, which takes it off her again (it takes off every face in the frame that she holds, so if she holds more than one there, they all go), and then This is Leo if the menu offers it. If the face you mean is smaller than another face that is not hers, the app has no way to pin it.
A circle that is not a face — Not a face — hide
Face detection takes a plush toy, a poster or the back of a head for a face now and then, and two of those in two frames is enough for a circle. Right-click the circle in the People section and choose Not a face — hide.
The circle goes at once, and a message says what happened: Not a face — 2 faces put aside · nothing about the frames changed. Those faces are remembered as not faces in the library: neither scanning new photographs nor any other correction draws the circle again, they are not shown in In this frame, and This is Maya never pins one of them. If the hidden circle was the selected person, its chip goes with it and the rest of the pass stays as it was.
There is no way to take Not a face — hide back inside the app. Use it only on a circle that is plainly not a face. A circle of a real person you do not care about costs nothing to leave where it is.
What survives a later scan
Every correction on this page, and every name, is written to the library folder as you make it. A later scan — a new card copied in, a frame an import brings inside the library, or the library opened from a new place — keeps all of them: a name stays, a face taken away with Not Maya never returns to her, a face pinned with This is Maya stays hers, a pair you called Not the same stays apart, and a hidden circle stays hidden. Only the unnamed circles are the scan's to regroup.
The one case that needs a second look is a face model arriving or going. Names stay, but in a frame with a very small face a name or a correction can land on a different face, and a hide that does cannot be taken back. When a face model arrives or goes says what to check.