Cell Text Fidelity

In each of these the transcription and the OCR agreed with each other — and a zoomed view of the page proved both wrong:

printed 0.99        → transcribed 0.98      (Age-to-Ultimate factor)
printed 2012.5-(A)  → transcribed 2013.5-(A)
printed 1.0400^(W)  → transcribed 1.04009^(W)

A disputed cell SHOULD be settled from a zoomed crop of the cell or from the word coordinates, and MUST NOT be settled by plausibility. "Plausible" is exactly what produced all three errors above: 0.98 is a perfectly reasonable factor.

• Typos stay. A word misspelled inside a cell MUST keep its misspelling.
• Numbers are copied digit by digit, with thousands and decimal separators exactly as printed. See Accounting Number Formats (§9.6.1).
• Wrapped codes are not fused with their neighbours. In a narrow column a code can wrap onto two lines, or two short codes can sit in neighbouring cells and look like one. The column boundaries and the cell's span decide: fusing B-2 with VC, or TR-1 with TR-2, is an error, and it also throws off the column count of the whole row.
• A blank cell stays empty. A cell that prints nothing MUST be rendered empty; a dash MUST NOT be supplied because the column has dashes elsewhere.

Some characters are visually identical and no zoom separates them: µ (U+00B5) and μ (U+03BC), a non-breaking space and an ordinary space, a minus sign and a hyphen.

• The output MUST keep the visible form and the character count exactly as printed, and SHOULD use the character normally typed for that glyph.
• The text layer MUST NOT be used to break the tie: it is a hint about the content, never the authority on it.
• A consumer or checker MUST treat the members of each family below as equal, so the choice among them cannot make an output non-conforming.

The image outranks every other source on what is printed. Where two codepoints are indistinguishable there is no fact about the page for it to be authoritative over — µ and μ are the same ink. The visible form is fidelity and stays exact; the codepoint underneath is a serialisation detail.

A dash that is doing something is not a homoglyph question. An em dash alone in a cell is a value — see Marks and Symbols in Cells (§9.6.6) — and a struck-through digit is not a character variant at all.

• Duplicated Tables (§9.2.4) — the rendered page decides whether a repeated table is really printed twice.
• Struck and Replaced Values (§9.6.7) — OCR silently joins a struck value to its replacement and produces a number that appears nowhere on the page. Only the image catches it.