Scan multiple pages into one PDF

Shoot the pages first

Put the paper on a plain surface with light coming from the side rather than from behind you, so your own shadow does not fall across the sheet. Hold the phone parallel to the page and fill the frame with it. A page shot at an angle is readable to you and awkward for anybody else, because the text runs downhill and the margins are uneven.

Shoot every sheet in order and do not stop halfway to check. Counting at the end is faster than working out later which of forty photographs is missing.

Turn the set into one document

Open Images to PDF and add all the photographs at once. Each image becomes one page. Drag the thumbnails into the right order before you build the file, because file names sort as text and put IMG_10 ahead of IMG_2.

Choose A4 or Letter as the page size for anything that will be printed, filed or sent to an office. Match, which sizes each page to its own image, is the right choice only for something that will be read on a screen. The JPG to PDF page describes the plain photograph case and sends you to this same tool until its own preset ships.

Nothing is resampled. The pixels from the camera go into the PDF as they are, which is why the file can be large and why the next section exists.

If your scanner app already made PDFs

Some scanning apps write one PDF per sheet rather than one image per sheet. Those are already PDFs, so they go through the merge tool instead, in the order you set on the page.

The result is the same document either way. What differs is that merging PDFs copies pages whole, so anything the app already did to the image, straightening, cropping, contrast, is carried across untouched.

The file will be big

Forty photographs from a modern phone is a PDF somewhere near 150 MB, which no mail system accepts. Compress the finished document as one step rather than shrinking each photograph first, so the pictures go through image encoding once.

Photographed paper is the easy case for compression. On the public bench run, scan type documents met their size target on 88.9% of cases, against 20.0% for pages that are mostly text, because a photograph of a page has far more room to give than a page of real text does.

Checking before you send it

Open the finished PDF and read one line on every page at normal zoom. If you cannot read a line, neither can the person receiving it, and reshooting one sheet now is cheaper than being asked for the whole document again. Check the page count against the paper stack before you close the tool.

The image combining guide covers page size and margin choices in more detail, and the phone scanning guide covers getting a photograph to look like a scan rather than a snapshot.

Crop and straighten before you build

Fix the photographs while they are still photographs. Every phone gallery can crop to the edge of the sheet and rotate a few degrees, and doing it there takes seconds per page.

Once the images are inside a PDF that work is much harder, because a page is not an image any more. Cropping then means changing the visible area of the whole page rather than the picture on it, and straightening a page that was shot at an angle is not something any PDF tool does. Five minutes in the gallery saves rebuilding the document.