Every image begins at a point. At the top of the column, a tungsten needle so sharp its end is a few hundred atoms wide lets two electrons go in the same femtosecond. By the bottom of the accelerator they are moving at seven tenths the speed of light, and they have not yet noticed each other.
Speed buys smallness. As the voltage climbs, each electron's wavelength shrinks far below anything light can manage, until the spacing between atomic planes starts to look roomy.
No glass bends an electron, so the column focuses them with magnetic fields, and inside a magnetic lens an electron does not travel in a line; it spirals. The two of them corkscrewed down together, turn for turn, through lenses that are honest about almost everything.
Honest about almost everything: rays that pass far from the axis focus short of the rays that hug it. A perfect point becomes a small apology, and the whole craft of high resolution is the management of that apology.
The foil was sixty nanometers thick, thinner than a soap bubble's wall. Electron A grazed a plane of atoms at exactly the angle the lattice likes, and was turned, losing nothing. Electron B hit the crowd, left some of its energy behind as heat and a bruise, and wandered on with a blurred memory of where it had been.
Signal and noise are not different substances. They are the same electrons, sorted by what they paid at the foil: the elastic ones keep the crystal's geometry in phase, the inelastic ones keep only a receipt for the energy they left behind.
A detector does not take a picture. It keeps score. One dot at a time, the electrons voted, and most votes landed nowhere in particular. The spots are simply the places where the elastic ones could not disagree.
The same pattern, at three honesties of exposure. Statistics is not a nuisance on top of the physics; at this scale, it is the physics.
You have never seen an atom. Neither have I. What we have is sharper than seeing: a way to ask a billion electrons the same question, and to keep only the answers they agree on.
A micrograph is not a photograph.
It is a census.
I spend my days asking.