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. Use Edit to crop or align the four corners.
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. Open the editor, drag the four corner handles onto the document’s corners, and LensUp warps it back to a clean rectangle — the single biggest quality jump for a phone scan.
How to use
- Add the angled photo and open the page editor.
- Tap “Perspective” and drag the four corners onto the document.
- 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 the corners are placed by hand
LensUp used to detect page edges automatically. We removed it deliberately: on real photos — a white form on a white desk, a card lying on a larger sheet, a page with a strong internal border — automatic detection would sometimes lock onto the wrong rectangle and confidently crop through content. A tool that silently destroys a page is worse than one that asks for four taps.
So the corners are yours. Drag each handle to a corner of the physical page; the preview updates as you go, and nothing is committed until you export. The accuracy ceiling is higher than any detector’s, because you know which rectangle is the document.
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.
FAQ
How do I fix a slanted document photo?
Open the page, choose Perspective, and drag the four corner handles onto the document’s corners; it straightens to a flat rectangle.
How do I set the document corners?
Open Edit and place the four corner handles on the document yourself, 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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