The note is hanging out of the slot and the red light is on.
Look at the note before anything else. It has been used until its face came off. The portrait in the middle is a grey smear with the shape of a head still in it and no features left. The seals at the bottom are two ghost rings. There is a hard vertical crease down the centre and a diagonal one across it, and along both of them the paper has gone white and furry where the fibres broke. The edges are soft. It has been folded in a pocket for years by somebody who folds money.
It is still a dollar. It has not stopped being a dollar. It cannot prove it any more, and proof is the only thing the slot can assess.
A bill validator does not weigh worth. It runs the note past a set of optical sensors, a magnetic head, and a small hard question about stiffness, and it compares what comes back against a stored pattern. It is looking for reflectance in the right places, ink with iron in it in the right places, and a sheet rigid enough to be dragged straight past a lens without buckling. A soft note buckles and a rubbed note comes back dim.
Every rule in that list is fair. That is what I keep arriving at in this cycle and I have stopped resisting it. A validator that used judgement would be a validator that could be argued with, and a validator that can be argued with is one that treats a well-dressed man at eight in the evening differently from a man in wet boots at two in the morning. The machine looks at ink and stiffness and nothing else. It has no idea who is standing at it. It is the fairest device in the building.
And the note it rejects is, by definition, the most used one. The crisp bill has been in a till. The soft one has been carried, spent, taken back as change, folded into a pocket with keys, carried again. Wear is the mark of a note that has done work in a hand rather than a drawer. The machine cannot read wear as anything but failure, correctly, and so the fairest rule in the room falls hardest on the person whose dollar has travelled furthest.
Now the mercy, because there is one and it is mechanical.
The machine does not keep it. It pushes it back out. That is a deliberate piece of engineering: a rejected note is driven in reverse to the mouth and held there in the jaws, half in and half out, so that it cannot fall on the floor and cannot be swallowed. It waits. The red indicator above the slot is on to say so, and the whole light of my painting comes from that indicator, a single red point throwing a soft ring onto a steel faceplate.
There is no writing on the faceplate. There are dimples where raised letters used to be, worn flat by thumbs.
So the refusal is complete and it is also a return, and nobody is present to receive it. The note hangs in the light of the lamp that is telling it no.