Most of us no longer own a scanner, yet we’re constantly asked to “upload a scanned copy”: a passport for a rental application, a signed form for HR, receipts for an expense claim, a doctor’s letter for insurance. A phone camera can do the job well, but a quick snap on a kitchen table often produces a dark, skewed, 8 MB image that an upload form rejects. This guide covers how to capture, convert and optimise documents so the result is clear, small and searchable. Our JPG to PDF converter combines photos into a PDF in your browser.
Step 1: capture a good image
The quality of the final PDF is decided at this step.
With a phone
- Lighting: use bright, even, indirect daylight. Avoid the phone’s own shadow falling across the page; hold the phone slightly to one side or use two light sources. Turn off the flash, which causes glare on glossy paper.
- Background: place the page on a dark, plain surface so the edges are easy to detect.
- Angle: hold the phone directly above the page, parallel to it. Tilted shots produce trapezoid shapes and blurry corners.
- Focus: tap the screen to focus on the text, and hold still.
- Fill the frame but leave a small margin around the page.
- Use a scanning mode: the iPhone Notes app, Google Drive on Android, Microsoft Lens and many built-in camera apps detect edges, correct perspective and boost contrast automatically.
With a flatbed scanner or office copier
- Clean the glass; dust shows up as specks.
- Close the lid to avoid dark edges.
- Choose the resolution and colour mode deliberately (see below) instead of the default.
Step 2: choose resolution and colour mode
| Document | Colour mode | Resolution |
|---|---|---|
| Plain text letters and forms | Black and white or greyscale | 300 dpi |
| Documents with stamps, signatures or highlights | Colour | 200–300 dpi |
| ID documents (passport, driving licence) | Colour | 300 dpi |
| Receipts | Greyscale | 300 dpi (small, faint print) |
| Photos | Colour | 300–600 dpi |
300 dpi is the sweet spot for documents: sharp enough for OCR and printing, without huge files. A colour A4 page at 600 dpi is four times the pixels of 300 dpi and rarely needed.
Step 3: clean up the image
Before converting, make sure each image is:
- Cropped to the page edges.
- Straight (rotated so lines of text are horizontal).
- Perspective-corrected so the page is rectangular.
- High contrast: the background close to white, text dark.
- In the right order for multi-page documents.
Most scanning apps do this automatically. If not, a basic photo editor can crop, rotate and adjust brightness and contrast.
Step 4: convert to PDF
- Open the JPG to PDF converter.
- Add the images in page order (drag to reorder if needed).
- Choose the page size (A4 in most countries, US Letter in the US and Canada) and margins.
- Create and download the PDF.
Need to go the other way, for example to send one page as an image or put a PDF page into a presentation? Use PDF to JPG.
Step 5: make it searchable with OCR
A scanned PDF is just pictures of text. OCR (optical character recognition) analyses the shapes of letters and turns them into real text. Benefits:
- Search the document (Ctrl+F / Cmd+F) for names, dates or amounts.
- Copy and paste text instead of retyping it.
- Screen readers can read the content aloud, improving accessibility.
- Search engines and document management systems can index it.
Our image to text tool extracts text from a photo or screenshot. Some PDF tools add an invisible OCR text layer behind the image, so the page looks unchanged but becomes searchable.
Getting accurate OCR
- Scan at 300 dpi; below about 200 dpi accuracy drops quickly.
- Keep lines straight and the page flat; curved book pages cause errors.
- Choose the correct language, especially for accented characters.
- Expect mistakes with handwriting, unusual fonts, faint receipts and tables; always proofread important figures such as amounts, IBANs and dates.
Step 6: keep the file size under control
Upload portals often cap files at 2–10 MB, and email at 25 MB. Rough guide for a typical A4 page:
| Settings | Approximate size per page |
|---|---|
| Black and white, 300 dpi | 50–150 KB |
| Greyscale, 300 dpi, compressed | 200–500 KB |
| Colour, 300 dpi, compressed | 300 KB – 1 MB |
| Uncompressed phone photo | 2–5 MB |
If your PDF is still too big, see our guide to compressing PDFs. Resizing photos before conversion also helps; see image optimisation.
Privacy and security
- Identity documents contain sensitive personal data. Prefer tools that work in your browser or on your device rather than uploading to unknown servers.
- Delete copies from shared devices, downloads folders and cloud “recent” lists after use.
- Consider adding a watermark such as “Copy for [company] rental application, October 2026” to ID scans to limit misuse.
- Never send ID scans in response to unsolicited emails or messages.
Common mistakes
- Shadows or glare obscuring part of the page.
- Cutting off page edges, stamps or signatures.
- Uploading sideways or upside-down pages.
- Scanning in colour at 600 dpi and ending up with a 40 MB file.
- Trusting OCR output for numbers without checking.
Checklist
- Even light, dark background, phone parallel to the page.
- 300 dpi, greyscale for text, colour only when needed.
- Crop, straighten and order pages.
- Convert to PDF with the correct page size.
- Run OCR if the text needs to be searchable.
- Check the file size against the upload limit.
- Store and share ID scans carefully.