Phone scanning tips for clean, readable PDFs

The quickest way to get clean phone scans is to fix the light, the background and the angle before you press the button. A scanner app can straighten and whiten a page, but it cannot invent detail that the camera never captured. These document scanner tips take a few seconds each and make a visible difference, whichever scanner app you use.

Light: the tip that matters most

Most poor scans are lighting problems, so the first document scanner tips are all about light.

• Use soft, even light. Daylight from a window beside you is ideal. Avoid direct sun, which creates hard shadows and glare.
• Kill your own shadow. If you stand between the lamp and the page, your head and phone cast a dark patch. Move so the light comes from the side.
• Turn off the flash for matt paper. Flash often makes a bright hotspot in the centre and darker corners.
• Use the flash for glossy paper only if tilting causes reflections. Try a slight angle first.

If the page looks grey in the camera preview, it will look grey in the PDF too. Add light rather than relying on filters.

Background: give the scanner a clear edge

Scanners find the page by looking for its edges. Help them:

1. Put white paper on a dark surface, such as a wooden table or a dark folder.
2. Clear other papers, cups and cables out of the frame.
3. Leave a small gap of background all around the page.

A white page on a white tablecloth is the classic reason a scanner cannot find the corners.

Angle and distance

• Hold the phone flat and directly above the page, parallel to it. The more you tilt, the more the app has to stretch the image, and the softer the text becomes.
• Fill most of the frame with the page, but not all of it.
• Steady your elbows on the table, or hold the phone with both hands.
• Wait for focus. Tap the middle of the page if the preview looks soft.

Flatten the paper

Folds and curls throw shadows and bend lines of text. Before scanning:

• unfold letters and press them flat under a book for a minute;
• for receipts that curl, hold the ends down with two coins outside the text area;
• for books, scan one page at a time and press gently near the spine.

Pick the right filter for the document

• Black and white for printed text, contracts and forms. Smallest files, sharpest letters.
• Greyscale for faint pencil, light stamps or faded paper.
• Colour for ID cards, certificates with coloured seals, photos and charts.

When in doubt, scan in colour with clean-up. You can always make a black-and-white copy later, but you cannot add colour back.

Check every page before saving

1. Zoom in on the smallest text, such as dates, reference numbers and signatures.
2. Look at the corners to make sure nothing is cut off.
3. Check the page order and orientation.
4. Retake any page that is blurry or has glare.

Rescanning one page takes seconds. Being asked to resend the whole document can take days. Of all the document scanner tips here, this habit saves the most time.

Trim and tidy after scanning

Even a good scan may have a sliver of table along one edge or wide, uneven margins. Cropping makes pages look professional and can shave a little off the file size. The guide to cropping PDF pages shows how to trim margins after the fact.

Make the result useful, not just readable

A scan is a picture of text. Adding OCR turns it into a document you can search and copy from, which is helpful for long contracts and reports. Clean, high-contrast scans give OCR the best chance of reading every word correctly. See how to make a scanned PDF searchable.

Document scanner tips for common problems

Text looks blurry. The phone moved or did not focus. Steady your hands and wait a moment after the preview sharpens.

One side is darker. Uneven light. Turn so the light falls evenly or add a second light source.

Lines of text are curved. The paper is not flat. Press it down, or scan a book one page at a time.

Scanner keeps missing the edges. Not enough contrast. Use a darker background.

File is huge. You scanned in colour at full size. Use black and white for text pages, or compress the PDF afterwards.

Scanning with PDF Burrow

The Scan to PDF tool in PDF Burrow photographs documents, auto-cleans each page and exports one PDF on your phone. After scanning you can trim edges with Crop / Trim Pages, fix the order with Organize Pages, and add searchable text with Make Searchable (OCR). For a step-by-step walkthrough of the scan itself, read how to scan documents to PDF with your phone.

Frequently asked questions

Should I clean my phone's camera lens before scanning?

Yes. A fingerprint smudge on the lens makes everything look hazy and soft. Wipe it with a soft cloth before an important scan.

Is it better to scan at night with a lamp or wait for daylight?

Daylight from a window is usually more even. If you must scan at night, use a lamp placed to one side and avoid shadows from your own body.

Why do my scans look yellow?

Warm indoor lighting tints the page. Use the clean or black-and-white filter, which corrects the background to white.

How can I scan very small receipts clearly?

Move closer so the receipt fills more of the frame, use bright even light, and choose black and white. Thermal receipts fade over time, so scan them soon after you get them.