How to Scan to PDF on a Mac

macOS has better built-in scanning than most people realise, spread across three places that each do the job slightly differently: Preview, the Printers & Scanners settings pane, and Image Capture. Plus a fourth that is genuinely the best option for a page or two and involves no scanner at all. Here is what each is good for and the settings that determine whether the result is usable.

Preview: the everyday route

Preview scans, which surprises people who have used it only as a viewer.

1. Open Preview.
2. File → Import from Scanner, and pick your device. If it is a networked MFP, it appears here once macOS has discovered it.
3. Tick Show Details — this is the important step, because the compact dialog hides everything worth setting.
4. Set Kind (Colour / Greyscale / Black & White), Resolution, Size, and the destination folder.
5. Set Format to PDF and, for a feeder, tick Combine into single document.
6. Scan.

The Details pane is where the useful options live: Auto selection for detecting page edges or separate items on the glass, Image Correction for exposure, and the duplex option when the scanner supports it. Without Show Details you get whatever the last person's settings were, which is the source of most "why is my scan enormous / grey / cropped wrong" confusion.

Preview will not OCR. The output is images in a PDF wrapper.

Printers & Scanners: the same engine, fewer clicks

System Settings → Printers & Scanners → [device] → Open Scanner gives the identical dialog Preview presents, without opening Preview first. Same options, same Show Details caveat. Use whichever you reach faster.

Image Capture: for volume and control

Image Capture (in Applications/Utilities) is the venerable, slightly unloved app that gives you the most control:

• Per-scan naming and format, including PDF, TIFF, JPEG and PNG.
• Auto-open in an application after scanning, which lets you pipe scans directly into another tool.
• Scan to a folder, with the Combine into single document option for feeders.
• Automator integration: Image Capture's device support is what Automator's scanning actions use, so a repeated scan-and-process workflow can be automated properly.

If you scan the same kind of document repeatedly, an Automator or Shortcuts workflow built around Image Capture — scan, OCR, rename by date, file into a folder — is the closest macOS gets to the manufacturer profile systems on Windows.

The one most people should use: Continuity Camera

For one to five pages, this beats every flatbed:

1. In Finder, right-click in a folder (or in a document, use File → Import from iPhone).
2. Choose Import from iPhone or iPad → Scan Documents.
3. Your phone wakes with the camera ready. Photograph the pages.
4. Tap Save, and the PDF appears on the Mac, in the folder you right-clicked.

The phone does edge detection, perspective correction, and contrast enhancement, and the result on ordinary printed paper is frequently better than a flatbed scan — because the processing is genuinely good and because you are not fighting a lid, an alignment mark and a warm-up cycle. The equivalent standalone workflow is covered in scanning documents with your phone.

Its limits: bound books and fragile originals still want a flatbed, and it is not a batch tool.

Manufacturer software on macOS

Epson ScanSmart, Canon's utilities, Brother iPrint&Scan, HP Smart and ScanSnap Home all have Mac versions, and the same argument applies as on Windows: they bring OCR, deskew, blank-page removal and profiles, none of which macOS provides. If you scan regularly, install the vendor tool despite its aesthetics.

The one macOS-specific annoyance is that vendor scanner drivers have repeatedly broken across major OS releases. Apple's built-in ICA drivers keep working, which is a real argument for using Preview or Image Capture for basic jobs and reserving vendor software for the features you actually need.

The settings that matter

Resolution. 300 dpi for text, 400–600 for small print or serious OCR, colour photographs 300–600 depending on reuse. Preview's Resolution dropdown defaults vary by device and are often set to something inappropriate. The reasoning: scanning resolution and DPI for documents.

Kind. Greyscale for documents unless colour carries meaning. Black & White (bilevel) produces the smallest files and destroys faint pencil, light stamps and photographs — appropriate for crisp printed text and nothing else.

Combine into single document. Off by default in some macOS versions, which is how you end up with Scan 1.pdf through Scan 24.pdf. If that has already happened, how to combine PDF files fixes it.

Auto selection: Detect Separate Items. Useful for scanning several receipts or photographs laid on the glass at once — each becomes its own page or file. It also misfires on documents with white margins, so turn it off for ordinary paper.

Size. Set it to the paper size rather than leaving it at whatever the last job used, or you will get A4 content on a Letter-sized canvas with a strip of black at the edge.

Adding OCR

macOS has no built-in PDF OCR, but three good options exist:

• OCRmyPDF via Homebrew: brew install ocrmypdf, then ocrmypdf --deskew --rotate-pages in.pdf out.pdf. Free, excellent, scriptable, and handles a whole folder in a loop. This is the recommendation for anyone comfortable with a terminal.
• Adobe Acrobat: Scan & OCR → Recognise Text, if you have it.
• macOS Live Text, for grabbing text out of a scan interactively — open the PDF in Preview, select text on the image directly. It works surprisingly well, does not modify the file, and is perfect for pulling a reference number out of a scan without any tooling.

Background: PDF OCR explained.

Post-scan cleanup in Preview

Preview handles most of the tidying without another tool:

• Rotate pages: select thumbnails, ⌘R.
• Delete pages: select in the thumbnail sidebar, press Delete.
• Reorder: drag thumbnails.
• Merge two scans: drag one file's thumbnails into another file's sidebar.
• Crop: select an area on a page, Tools → Crop.
• Reduce file size: File → Export → Quartz Filter → Reduce File Size. Be warned that this filter is aggressive and old, and frequently makes text unpleasantly soft. Better options are in how to compress a scanned PDF.

Remember that Preview saves in place by default; ⌘⇧S (File → Duplicate, then save) if you want to keep the original.

A sensible default workflow

For a Mac-based office:

• One or two pages, no scanner needed → Continuity Camera into the destination folder.
• A stack of pages → feeder scan from Preview at 300 dpi greyscale, combined into a single PDF.
• Anything to be kept or searched → OCRmyPDF afterwards, ideally as a folder action so it happens automatically.
• Anything with a retention requirement → export to PDF/A; see PDF/A archival format explained and how to archive PDFs long term.
• Consistent filenames at scan time, not later: naming and versioning shared files.

Summary

Preview's Import from Scanner with Show Details turned on covers most scanning on a Mac; Image Capture adds automation; the vendor's software adds OCR and deskew if you scan often. For a handful of pages, Continuity Camera from your iPhone is faster and usually produces a better image than the scanner sitting next to you. Scan at 300 dpi in greyscale, combine into a single document, and add OCR afterwards with OCRmyPDF.