How to Scan a Document With Your Phone: Clear PDF Scans

A phone camera can make a clean PDF scan of a paper document, as long as the photo is taken well. Most bad scans have the same three causes: shadows across the page, a background that looks like the paper, and a phone held at an angle. This guide shows how to avoid all three, then how to turn the photos into one straight, cropped PDF with SafeResize.

Everything happens on your phone or computer. Your pages are not uploaded, and the camera view is not recorded or sent anywhere.

What makes a good scan

• Even light. No shadow of your hand, your phone or your head on the page.
• A plain, different-coloured background. White paper on a dark table shows its edges clearly. White paper on a white desk does not.
• A flat page. Creases and curls bend the text.
• A straight view. Hold the phone directly above the page, not to one side.
• The whole page in view, with a little space around it.

Step 1: set up the page

Lay the page flat on a plain surface. A dark desk, a dark cloth or a sheet of dark card all work for white paper. If the paper is dark or coloured, use a light surface instead. The idea is that the edge of the page stands out, because the tool looks for the page by its edge.

Turn towards a window. Daylight from the side or from in front of the page is softer than a lamp overhead, which throws the shadow of your phone right onto the paper. If you have to use a lamp, move it to one side.

A page that will not lie flat, such as one from a book or a folded letter, is the hardest. Press it flat with your free hand at the very edge, or put a coin or a small object on each of two corners, outside the text. The tool straightens a page that is seen at an angle, but it cannot smooth out a page that is curled.

Step 2: add your pages

Open Scan documents to PDF. You have two ways to add pages.

With the camera. Press "Use the camera" and allow the camera when your browser asks. The rear camera opens first. Point it at the page. A live outline shows the page the tool has found. It turns green when the tool thinks it has found the page, so still check each page afterwards. The message under the picture says "It looks like a page. Hold still, then press the round button." Press the round button, then move on to the next page.

• Undo takes back the last photo.
• Torch lights the page, on phones that have a torch. It is a light on the phone, so it can leave a bright patch on shiny paper. Use it only in a dark room.
• Other camera switches between the front and back cameras, if your phone has more than one.
• Done ends the camera and takes you to your pages. Close throws the photos of this visit away, and asks you first.

The camera only works on a secure page (a web address that starts with https), and only after you allow it. If it is blocked, tap the camera or lock icon next to the address, choose Allow and try again. Or choose photos instead.

With photos you already have. Press "Choose photos" and pick them from your gallery or files. JPG, PNG, WebP and HEIC photos work, although some browsers cannot open HEIC. You can pick several at once.

The camera in the page asks for a picture of about Full HD size (1920 × 1080 pixels). That is enough for most documents. If a page has very small print, take the photo with your phone's own camera app, which uses the whole sensor, and add it with "Choose photos".

You can add up to 30 pages to one PDF.

Step 3: check each page

Each page appears in a list, already straightened. Look at every page and make sure it is straight and shows the whole paper.

• Adjust corners. If the outline missed an edge, press this and drag the four round handles onto the corners of the page. A magnifier shows the spot under your finger. With a keyboard, Tab to a handle and use the arrow keys. "Reset to detected edges" starts again, and "Use the whole photo" puts the corners at the edges of the picture.
• Rotate turns the page a quarter turn to the right.
• The up and down arrows move the page in the list. The PDF follows the order of the list.
• The cross removes a page.
• Tap the picture to see a bigger view.

The tool sorts each page into one of three cases:

• Confident. There is no warning. Look at the page anyway.
• Unsure. The page says "We found an outline, but please check the edges." The outline is often right, but check each corner, and use Adjust corners if one is off.
• Not found. The page says "We could not find the page. We kept the whole photo, so drag the corners onto the page." Nothing was outlined, so the whole photo is shown. Use Adjust corners and drag the four corners onto the page.

The page finder does not always get it right, even when it is confident. A page that fills the whole frame, or runs past the edge of it, is the hardest: drag its corners to fit. Two pages of an open book, or any two-page spread, are outlined as one page. Photograph each page on its own if you want them separate.

Step 4: choose a look

You choose one look for all pages, and a page can have its own.

Two things to know. Auto and Grey turn pale paper, such as cream or light yellow, white. If the colour matters, choose Original. And Black and white turns a photo on the page into a fine pattern of dots, so use Grey or Auto for pages that have a photo.

Step 5: choose the PDF and download

On the last step you choose:

• Page size: Auto, A4 or US Letter. With Auto, each page keeps the shape of its scan. A scan close to A4 or US Letter becomes that real paper size, and other shapes, such as a receipt, keep their own proportions.
• Two scans on one page. Tick this for the front and back of an ID card. The first scan goes on top and the second below it. There is a page for this: scan an ID card to one PDF page.
• File size limit: No limit, or under 200 KB, 500 KB, 1 MB or 2 MB. Sharpness is lowered only as far as needed to fit.

Press "Make my PDF". The file is called scan- followed by today's date, and the result shows a preview of page 1 exactly as it was saved, the number of pages and the size. Without a limit, pages are saved at 200 DPI, or at 150 DPI when there are more than 10 pages.

Each page in the PDF is a picture, so you cannot select or search the text in it. SafeResize does not read the text.

What to do about shadows and glare

• A shadow across the page. Move the phone or the light until it is gone, then take the photo again. Auto evens out light shadows, but it cannot bring back writing that is lost in a dark one.
• Your own shadow. Stand so the light comes from the side, not from behind you, so the shadow falls away from the page.
• A bright patch on shiny paper. Tilt the phone slightly, or turn away from the window or lamp, until the patch moves off the text. Do not use the torch.
• A page that looks bent. Press it flat and photograph it again. Dragging the corners fixes the angle but not a curl.

Common problems

• The outline does not turn green. The page may be too close in colour to the surface, or too much of it is out of view. Change the background, or take the photo anyway and drag the corners afterwards.
• The page is cut off at one edge. Move the phone back a little so all four corners are in view, or use Adjust corners.
• The text is blurry. Hold still until the photo is taken, and make sure the light is good. Blur cannot be taken out afterwards.
• The PDF is too big for the form. Choose Black and white, pick a size limit on the last step, or use Resize a PDF. The guide on making a PDF smaller goes through it.
• You have PDF files, not photos. This tool works from photos of pages and cannot open PDFs.

Keeping it private

The pages are found, straightened and saved on your own device. The live view is drawn on your screen only. It is not recorded, and nothing is sent to SafeResize or anyone else. The camera turns off when you press Done or Close, when you leave the page, and if the tab stays out of view for a while. Closing the page removes your pages from memory.

Be careful with a scan of an ID card or a passport, even so. Send the finished PDF only to the people who need it.