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Overview
A scanned page is a photograph of a document: no selectable text, just pixels. Conseal handles scans with OCR built in. It reads the text out of the image first, then runs the same detection you get on any other file. This guide covers what happens under the hood, and how to get the best results from your scans.
The flow is the same
Drop the scanned PDF or image in, pick a mode, let the scan run, review, redact, save How to redact a document with Conseal in 2 minutes. Conseal detects that the pages are images and reads them with OCR automatically. You don't switch anything on. As always, everything runs on your machine, offline included.
OCR reads the scan, page by page
What's different underneath
On a digital document, Conseal reads the text directly. On a scan, it reads the image, so the quality of the input shapes the result:
- Detection quality follows scan quality. A crisp 300-DPI scan reads nearly as well as digital text, and the cleaner the page, the sharper the detection.
- Positions come from the image. Redaction boxes are placed where OCR measured the text on the page. Clean, straight scans give the most precise placement, which is one more reason good scans pay off.
Getting a better scan
Five habits fix most problems before they happen:
- Scan at 300 DPI or higher when you control the scanner
- Keep pages straight; skew is the biggest single cause of misreads
- Prefer black-and-white or grayscale over color for text documents
- Photographing instead of scanning? Flat page, straight-on angle, even light, no shadows
- Rescan rather than fight a bad scan. Two minutes at the scanner beats twenty at review
Review scans like you mean it
After the scan, work the PII Detected panel as usual How to review what Conseal detected, with two extra habits for scans:
- Check box coverage in the document view. Confirm each highlight fully covers its text, including edges, before you redact.
- Sweep for anything extra. Use Find in document for surname fragments, and mark anything you want hidden with the cursor or the pen tool, which was built with scans in mind How to redact something the AI missed. Attach repeat mentions to the existing entity so labels stay consistent.
Then run Verify redaction before saving for a green confirmation that your selections are gone.