How to scan documents with your phone and get a clean PDF
By the PdfDady team · Updated · 6 min read
A phone camera makes a perfectly good scanner if you get three things right: even light, the page lying flat on a dark surface, and the corners straightened afterwards. Do those, pick black and white for text pages, and the PDF will look like it came out of an office scanner rather than off a bedsheet.
Our Scan to PDF tool handles the after-part in your phone's browser. You take or add photos, drag four corners to the edges of each page, pick a look, and save one PDF. Nothing is uploaded and there is no app to install.
Set up before you take a single photo
Most bad scans are decided before the shutter is pressed.
Light. Daylight from a window is ideal. Stand so the window is to one side, not behind you, or your own shadow lands on the page. At night, an overhead tube light works if you lean back so your head and phone don't block it. Avoid the flash, especially on laminated cards and glossy certificates, where it leaves a white blob right over the text.
Surface. Lay the page on something darker than the paper: a wooden table, a dark bedsheet, the floor. The contrast makes the paper's edges obvious, which helps when you set the corners. White paper on a white table is the hardest case.
Flatness. Folded documents, like an old marksheet kept in a file for years, have creases that throw shadows. Press the page flat under a book for a few minutes first, or hold the corners down with coins outside the text area.
Angle. Hold the phone directly above the page, parallel to it. A small tilt is fine because the tool straightens it, but a steep angle stretches the far end of the page and makes small print at the top harder to read.
Scanning step by step
- Open Scan to PDF on your phone and tap Take a photo. You can also add photos you've already taken. JPG, PNG, WebP and iPhone HEIC are all accepted.
- Fill the screen with the page, tap to focus on the text, and hold still for a second before taking the photo.
- Drag the four corners to the corners of the paper. The preview shows the page straightened into a flat rectangle, with the table cut away.
- Choose a look. Black & white document for typed or printed pages. Enhanced colour when colour matters. Grayscale or Original for anything in between.
- Add the next page and repeat. You can add up to 50 photos.
- Reorder, rotate or delete pages if anything is out of place, then press Create PDF. The file is saved as
scan.pdf.
The page size can be A4 or the same shape as the scan. Choose A4 if the PDF may be printed, since that's the paper Indian offices and print shops use.
Which look for which document
Black & white document mode turns shadows and grey paper white and keeps the text black. It makes ordinary pages crisp and small. It is the wrong choice whenever a photo or colour is part of the document.
- Rent agreement, bank letter, typed application, printed bill: Black & white document.
- Aadhaar, PAN, voter ID, anything with your face on it: Enhanced colour. Black and white turns faces into dark blobs.
- Certificates with a coloured seal or a blue-ink signature that must show: Enhanced colour.
- Pencil notes or a faded carbon copy: Grayscale, then zoom in and check it's readable.
The Income Tax Department's own scanning tips ask for black and white scans (at 300 DPI) for its attachments. For text documents going to other portals, black and white is a sensible default too, unless the portal asks for colour.
Awkward documents
Two-sided documents. Photograph the front, then the back, as separate pages. For ID cards, our guide on preparing documents for KYC covers putting both sides on one page.
Bound registers and books. The page curves towards the spine, and the four-corner correction can't flatten a curve. Press the book open as flat as you can and photograph one page at a time, not the whole spread.
Long receipts. Photograph them in sections if needed, or step back so the whole strip fits and choose "same as the scan" for the page size, so a long, thin receipt isn't squeezed onto an A4 page.
Small cards. A single ID card photographed close up can look grainy because the phone struggles to focus very near. Move back a little and let the corner crop do the zooming.
After scanning: size and sharing
A colour scan of several pages can easily be a few MB, which is too large for many upload forms. Run it through Compress PDF. Smallest size lets you pick a target such as 100 KB or 200 KB and finds the sharpest version that fits. Black & white scans compress much better than colour, which is one more reason to use that mode for text.
If you already have photos of documents and just want them in one PDF without any straightening, Image to PDF places them on pages as they are. Scan to PDF is the better choice when the photos are tilted or show the table around the page. There is more on that route in our guide to converting phone photos into one PDF.
For the deeper side of file size and clarity, see how to make a scanned PDF smaller and clearer.
What a phone scan can't do
- The text isn't searchable. The PDF is made of images. Scan to PDF has no text recognition (OCR), so you can't copy text from it or search inside it.
- Curved pages stay curved. Correction is based on four corners, which suits flat sheets.
- It can't recover what the camera didn't capture. A blurry or shadowed photo stays blurry. Retaking it is faster than fighting it.
If your phone already has a scanner built in, that's a fine option too. On iPhone, the Notes app has Scan Documents under the attachment button. On Android, the Google Drive app has a camera button that scans to PDF. Use whichever you prefer. Ours is useful when you don't want the scan saved to a cloud account, or you're on a shared or borrowed phone.
Questions people ask
Is a phone scan acceptable for official uploads?
Usually, if it is clear, complete and the right size. Check the portal's instructions for format, size and colour. A sharp black and white scan of a typed page is generally better than a dim colour photo.
How do I scan several pages into one PDF?
Add each page as a new photo in Scan to PDF, check the order, and create the PDF once. All pages end up in the same file.
My scan is the wrong way round. Can I fix it?
Yes. Rotate the page in Scan to PDF before creating the PDF. If the PDF is already made, our Rotate PDF tool can turn pages permanently.
Are my photos uploaded?
No. They are processed in your browser and stay on your phone.