Straighten a photo into a flat scan
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Add
On a computer, drag images or PDFs here, or paste a screenshot (Ctrl / ⌘ + V).
Adjust
EffectWhitens the paper background; dark print stays dark.
Removes the color and adds a little contrast.
Keeps the original colors, with no tone change.
Pushes ink to black and paper to white; some gray can remain.
Evens out shadows and uneven light; keeps colored ink and stamps.
Fades blue, red and green ink; cannot reliably remove black handwriting.
Warm gray paper, fine grain and a slight tilt; colored ink turns gray.
Export
Export optionsA4 · Single · No limit
ID card: places the first two pages as front & back at ID-1 size on one A4 sheet. In the ID card tool, corners are proposed automatically when card edges are clear. Use Edit to check all four corners and adjust them by hand if needed.
PNG is lossless, so target sizes do not apply.
Uses original photos. Larger files and slower export. Available with No limit or PNG.
Optional. Keeps the image ratio and never exceeds the page.
Photograph a page at an angle and it comes out as a trapezoid. Corners are proposed automatically when document edges are clear. Check them and adjust by hand if needed.
How to use
- Add the angled photo and open the page editor.
- Corners are proposed automatically when document edges are clear. Check them and adjust by hand if needed.
- Apply — the page is warped flat, then export as usual.
Why photographed pages come out skewed
Point a camera at a page from anywhere but straight above and rectangles stop being rectangles: the near edge of the sheet is closer than the far edge, so the page renders as a trapezoid. This keystone effect is the single biggest reason a phone photo of a document looks like a photo instead of a scan.
Perspective correction reverses that projection. Mark the four corners of the page in the photo, and the tool remaps the quadrilateral back into a proper rectangle — the same transform a scanner achieves mechanically by holding the paper flat against the glass.
Why you check the corners
LensUp proposes the page corners automatically on photos with clear edges, but it never trusts that blindly: on real photos — a white form on a white desk, a card lying on a larger sheet, a page with a strong internal border — a detector can lock onto the wrong rectangle and crop through content. A confident result is applied; a less certain one only pre-positions the handles. LensUp can also propose corners on scanned PDF pages with clear edges. On text/vector PDF pages without a large page image, set the corners by hand in Edit.
So the final word is yours. Check each handle against a corner of the physical page and drag any that are off; the preview updates as you go. Done applies your edits; Export creates the output file.
Placing corners for a clean rectangle
Put each handle on the true paper corner, not the corner of the printed area — text blocks are rarely centered, and cropping to the print eats the margins a form needs. If a corner of the sheet is cut off by the photo’s framing, aim where it would be; extending the two visible edges in your eye is usually accurate to a few pixels.
A slightly generous placement is safer than a tight one. A millimeter of desk along one edge is invisible after the scan filter whitens the background; a millimeter cut off a table of numbers is not.
After straightening
Correction is the first half of the scan look; the filter is the second. Once the geometry is rectangular, the document filter levels the background and sharpens text, and the export places the straightened page onto A4, US Letter or its original dimensions. From there it can leave as a PDF or an image, alone or merged with the other pages of the batch.
Everything — the remap included — runs in your browser. A crooked photo of a contract does not need to visit a server to learn to stand up straight.
Edit an online scan image before export
Import the photographed page and position the four corners around the actual paper. Confirm the crop, inspect the straightened result and rotate it if needed. A perspective edit changes the geometry, not the wording of the document.
For several images, check each page separately and arrange the final order before saving. Use Color for photographs and White document when paper cleanup improves readability.
When to use the PDF editor instead
If the job is adding text or covering a local mark, export a PDF and open it in the PDF editor. Cover only hides underlying data unless you choose Remove it when downloading.
A geometric correction cannot recover text cut off in the source or reliably repair blur. The exported scan uses image pages rather than preserving a PDF text layer or interactive forms.
FAQ
How do I fix a slanted document photo?
Corners are proposed automatically when document edges are clear. Check them and adjust by hand if needed. Apply — the page is warped flat, then export as usual.
How do I set the document corners?
On photos with clear document edges, the four corners are proposed automatically. Open Edit to check the handles and adjust them by hand if needed, then apply the correction. The ID card layout only places the first two pages as front and back at ID-1 size; it does not change their crop.
Does it upload my photo?
No — the warp runs entirely in your browser.
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