Why a 2.4 µm Herculaneum scan still reads as noise — and what actually blocks it

I ran the public ink model on a 2.4 µm scan of sealed PHerc1203 and got speckle instead of letters. Chasing why turned up a mistake in my own measurement, corrected it against the community's winding atlas, and left me with something more useful than a failed read: a CPU-only gate that flags rendered windows unlikely to isolate one papyrus sheet — before you spend the GPU.