artifact index
| Artifact | Typical cause | Preservation note |
|---|---|---|
| Edge shadow | Bound packet, raised staple, uneven lid pressure | Keep the shadow if cropping would remove marginal information. |
| Vertical streak | Dirt on glass, calibration strip, or feeder slit | Rescan if possible; otherwise describe the streak in the item note. |
| Faded strike-through text | Carbon copy, low toner, old thermal paper | Grayscale master may hold more evidence than a clean bilevel derivative. |
| Photocopy snow | Repeated copy generations | OCR punctuation will be unreliable. |
| Deskew crop loss | Automatic correction after a crooked scan | Check signatures, stamps, and page numbers near corners. |
Several public collections are useful because they include imperfect scans instead of only polished exhibition images. I keep a short list on the source collections page.