Scan documents to PDF with your phone: photos, page size and privacy

Taking photos that read well

A few habits make more difference than any app setting:

• Use even light. Daylight from a window to the side works well. Direct overhead light tends to put the shadow of your phone and hand on the page.
• Watch for glare. Glossy paper and laminated cards reflect lamps and flash; tilt the card slightly or move the light.
• Lay the page flat on a plain surface that contrasts with the paper, such as a dark table under a white sheet. Flatten folds and curled corners.
• Hold the phone parallel to the page, directly above it, so the edges stay straight rather than forming a trapezoid.
• Fill the frame with the page, leaving a small border, and tap the screen to focus on the text.
• Check each photo before moving on: zoom in on the smallest print. If you can't read it, nobody else will.

A4 or US Letter

A4 is 210 × 297 mm, defined in ISO 216 and used in most of the world. US Letter is 8.5 × 11 inches (215.9 × 279.4 mm), used mainly in the United States, Canada and the Philippines and in parts of Latin America. Letter is slightly wider and shorter than A4.

Pick the size used where the document is going. If the receiver will print it, matching their paper avoids shrunken pages or cut-off edges. In our JPG to PDF tool, Page size offers Same as the picture, A4 and US Letter. Same as the picture makes each page exactly the shape of its photo, which is fine for viewing on screen but awkward to print.

Putting pages in order

Number the pages in your head before you start, and photograph them in that order; the files on the phone then sort the same way. In the tool, the list can be rearranged with the ↑ ↓ buttons or by dragging a row, so a missed page can be added and moved into place.

Orientation set to Automatic picks portrait or landscape to match each photo, so a landscape table and portrait letters can share one PDF. Margin can be None, Small (10 mm) or Large (20 mm). A small margin keeps the content away from the edge of the paper when the file is printed.

Making the file small enough to send

Phone photos have far more pixels than a page needs. Image quality has two settings: Original keeps the photos as they are, and Smaller file re-saves each one as JPG at 80% quality with the longest side at most 2000 px. That is usually plenty for reading and printing a document.

If the PDF is still too large for an email or an upload form, run it through Compress PDF. Its Strong mode turns each page into a lighter image, which suits scans, since their text is already part of the picture.

ID documents: keep the copies close

A copy of a passport, ID card or driving licence holds your name, date of birth, photo, signature and document number: much of what's needed to pretend to be you. Uploading it to an unknown converter site hands that file to a company whose storage and deletion you can't check.

Tools that run in the browser avoid that step: the photos are turned into a PDF on your own device and never uploaded. When you send the PDF, send it only to the organisation that asked for it, through their own form or address. Afterwards, delete spare copies from your downloads folder and photo gallery.

Adding to an existing PDF

If the scan has to go with a document you already have as a PDF, such as an application form, make the scan into its own PDF first, then join the two with Merge PDF. Open the merged file afterwards and check that every page is there, in the right order.