How to remove shadows from a scanned document
A document photographed on a desk rarely looks like a scan: the paper is gray, one corner is darker than the rest, the lamp adds a yellow tint and the page is a slanted shape surrounded by table. Clean up a scan fixes all of it in one pass, for photos and for scanned PDFs.
Updated September 28, 20264 min read
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Clean up a scan, step by step
Photos and scanned PDFs go in the same way; several files come out as one PDF.
- Open Clean up a scan and add the photos or the scanned PDF.
- Choose a look: Document, Grayscale or Black & white.
- Leave “Find the page and straighten it” on for photos taken at an angle.
- Run the tool and download the cleaned PDF.
Which look to choose
If the page has a color photo or a chart that matters, use Document.
- Document: shadows and yellow light go and the paper turns white, while ink keeps its color — signatures and stamps stay blue or red.
- Grayscale: the same clean-up in shades of gray, good for printing and smaller than color.
- Black & white: pure black text on white, the smallest file, and what fax and some court and government portals expect.
How the shadow comes out
The tool estimates how bright the bare paper is in every part of the page — darker under a shadow, warmer under a lamp — and evens it out, so the paper ends up white everywhere and the text keeps its contrast. A photo taken at an angle is straightened first: the four corners of the sheet are found and the page is opened out to a flat rectangle, so the table around it disappears.
If the corners come out wrong, scan with the camera tool instead: there you can drag each corner onto the paper before downloading.
Make it searchable afterwards
Cleaning redraws each page as an image, so a text layer from an earlier OCR is not kept. Run OCR PDF on the cleaned file to make the words searchable and copyable again — a clean page also gives better OCR results.