Preserve the batch before cleanup
Blank-removal settings use thresholds, not an understanding of the document. A faint mark, a page number or low-contrast pencil note may be meaningful even when most pixels are white. NAPS2 documents threshold adjustment when nonblank pages are removed, which is a reason to preserve the original batch.
Name the original and processed copies clearly. The report records each file’s SHA-256 so you can identify the exact inputs later. A file hash identifies a file; it does not say whether a changed PDF retained every meaningful page.
Interpret visual matches as candidates
The comparison renders pages sequentially, builds small grayscale rasters and looks for close matches. A missing candidate points to a page worth checking; deskew, rotation, a crop or an added stamp can also explain the difference. Nearly blank pages and repeated templates are treated as ambiguous because a thumbnail cannot identify them safely.
- Inspect every original page with no close candidate.
- Review ambiguous forms at full resolution.
- Do not equate a similar thumbnail with identical text.
- Keep numbered-page evidence and visual evidence as separate checks.
Make cleanup a reversible step
Reprocess confirmed exclusions from the untouched batch, then check the resulting PDF against the same reference. Preserve intentional blanks where the delivery requirements call for them. If there is no original batch, the tool can flag numbering anomalies but cannot reconstruct what the scanner discarded.
This release accepts at most 256 pages across a run and 80 MiB per PDF. Split larger archives into documented sections with their own counts and label ranges. The final review should also cover legibility, orientation, cropping and any source material outside the printed numbering system.