How to use Scan to PDF
- Take a photo of each page, or choose photos you already have.
- Check the corners on each photo; the tool places them on the page's edges, and you can drag them or move them with the arrow keys.
- Pick a look (original colour, greyscale or black and white) and A4 or US Letter, and put the pages in order.
- Select Make PDF and download the scan.
How the page is found
Each photo is shrunk to a small working copy, and the tool looks for the largest area that is clearly lighter than its surroundings. It fits the four-sided shape that best matches that area's outline, then fits a straight line along each edge and puts the corners where the lines meet. That is quick and needs no download, but it is a heuristic, not magic: it works best with a light page on a darker surface, all four corners in the shot, and even light.
When it can't find a page, for example a white sheet on a white desk, it says so and places the corners near the edges of the photo for you to drag. You can always adjust the corners, with a pointer or touch, or with the keyboard: Tab to a corner and use the arrow keys, holding Shift for bigger steps.
Straightening and the scan look
A photo taken at an angle makes a rectangular page look like a trapezium. The tool works out the perspective transform that maps your four corners onto a rectangle and redraws every pixel through it, so lines of text come out level and the page fills the frame. It also estimates the page's real proportions from the perspective, so a sheet shot at a slant isn't left squashed; that estimate assumes an ordinary phone camera and can be a little off for cropped or zoomed photos. Photos are turned the right way up first, using the orientation your phone recorded.
Original colour keeps the photo as it is. Greyscale drops the colour. Black and white compares each pixel with the brightness around it rather than with one fixed level, so text stays black and paper turns white even where a shadow or your phone falls across the page; it suits printed text and forms best, and can lose very faint pencil.
What happens to your photos
Photos are read into this browser tab, and all the work happens in a background worker on your device. Nothing is uploaded or stored. Each page is placed on A4 or US Letter, turned landscape for wide pages, and the finished PDF carries no author or dates. To make the text searchable, run the result through OCR PDF.
Questions
- Does it always find the page edges?
- Not always. It looks for a page that is lighter than what it lies on, so a white sheet on a dark desk works best. On a white table, in deep shadow, or with the page cut off, it may miss; then drag the corners into place yourself.
- Are my photos uploaded?
- No. Edge finding, straightening, the filter and the PDF all run in your browser tab. Photos never leave your device.
- Can it read the text?
- This tool makes a picture of each page. To make the text searchable and selectable, run the PDF through OCR PDF afterwards; it also works in your browser.
- Which look should I choose?
- Black and white suits printed text and forms: it whitens shadows and keeps files small. Greyscale keeps pencil and faint marks. Original colour keeps stamps, highlighter and photos.