How to Deskew a Scanned PDF for Clean, Straight Pages

Straighten skewed scans so pages sit level — improves OCR accuracy and document quality.

3 min readDeskew scans

The auto-feeder skewed every page by 3 degrees. The whole PDF reads at an angle. OCR accuracy collapses. Printed copies look amateur.

Deskewing rotates each page back to level. Automatic for most cases, manual fine-tune for the rest.

Spot the skew

Look at any page of the scan. If horizontal lines (rule lines, table edges, top of the page text block) aren't perfectly horizontal, the scan is skewed.

Even a 1-2 degree skew degrades OCR. 5+ degrees looks visibly wrong.

Deskew automatically

Open the PDF in Flint's editor and run deskew. The tool detects text baselines on each page and rotates to align them.

Does the work on every page at once. For a 50-page scan, takes a few seconds.

Then OCR for searchability

Run OCR after deskewing. Straight pages are 95%+ accurate for OCR; skewed pages drop to 70-80%.

The two together — deskew, then OCR — turn a wobbly scan into a clean searchable document.

FAQ

Will deskewing crop my pages?

Slightly — rotated pages need to expand or crop at the edges. Most tools default to expanding (whitespace added) rather than cropping.

Can deskew fix pages skewed in different directions?

Yes. The tool analyses each page independently and rotates accordingly.

Why does my OCR accuracy stay low after deskewing?

Skew is only one factor. Low contrast, faded text, or unusual fonts also affect OCR. Try increasing scan contrast before deskewing.

Should I deskew before or after compression?

Deskew first. Compression after rotation is cleaner; rotating compressed images loses quality.

Deskewing fixes a small problem with outsized effects. Open the scan in Flint's editor, straighten, then OCR.

Try it now

Drop a PDF in and you'll be done in seconds — no install, files private to your account.

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How to Deskew a Scanned PDF | Flint — Flint PDF