Sending back signed contract pages
Photograph the signed pages, straighten and binarize them, merge one PDF and send it back looking as crisp as a scan.
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Guide
Scan enhancer makes quick phone photos of documents look like they came from a scanner: drag the four dots onto the corners of the sheet and a perspective transform flattens the skewed page into a rectangle; then pick an enhancement mode — Color enhance applies auto contrast plus sharpening, Grayscale removes color before enhancing, and Black & white document runs Otsu thresholding to produce pure black and white; finally, several photos can be merged into one PDF in the order you set, or downloaded one by one as processed images.
Updated 2026-09-094 min read
Scan enhancer makes quick phone photos of documents look like they came from a scanner: drag the four dots onto the corners of the sheet and a perspective transform flattens the skewed page into a rectangle; then pick an enhancement mode — Color enhance applies auto contrast plus sharpening, Grayscale removes color before enhancing, and Black & white document runs Otsu thresholding to produce pure black and white; finally, several photos can be merged into one PDF in the order you set, or downloaded one by one as processed images.
It only works on images and does not recognize text. If you need to search or copy text from the merged PDF, follow up with PDF OCR. If the photos are already straight and you just want a batch PDF, Image to PDF is the direct route.
| Input | Output | Notes |
|---|---|---|
3 skewed photos of a contract, Black & white document, A4 |
scanned-document.pdf, 3 portrait A4 pages, pure black and white |
merging several photos always names the file scanned-document.pdf |
1 landscape photo of an invoice, Color enhance |
invoice_scanned.pdf, A4 turned landscape automatically |
a single photo is named <original-name>_scanned.pdf |
the same batch via Download processed images |
scan-enhanced-images.zip with 001_invoice.jpg, 002_… |
the numbers are the page order |
Photograph the signed pages, straighten and binarize them, merge one PDF and send it back looking as crisp as a scan.
Snap each invoice and ticket, enhance in color and merge them in order into a PDF that finance can review.
Process to a black-and-white PDF and hand it to PDF OCR; recognition is better than from the raw photo.
This version has no edge detection, so you place the dots on the sheet corners yourself; the default dots sit at the image corners, which means “enhance only, no crop”. The closer you drag them to the edges, the better the straightening.
Black & white document thresholds every pixel to pure black or white with Otsu's method, so red stamps and grayscale pictures are simplified. Use Color enhance or Grayscale for pages like that.
A4 picks the paper orientation from each image and fits it proportionally with white margins, which suits printing; Match image ratio keeps the page A4-wide while the height follows the image and leaves no margins, which suits on-screen reading.
Perspective correction, enhancement and PDF merging all happen in your browser; the images are never uploaded to any server, and the data is released from memory when you close the page.
Updated 2026-09-09
Straighten phone photos of documents with four-corner perspective correction, auto contrast / black-and-white, combine pages into a PDF
Documents, contracts and receipts shot on a phone; drag the four corners to fix perspective, then enhance and combine into a PDF in one click