Redacting a single PDF is straightforward. Open the file, find the sensitive data, apply redaction, save. Even with basic tools on macOS, a one-off document takes only a few minutes. But what happens when you have 50 files? Or 200? What if you need to process an entire archive of contracts, employee records, or case files before a disclosure deadline?
That is the reality for legal teams preparing discovery productions, compliance officers responding to FOIA requests, and HR departments archiving personnel files. The manual, file-by-file approach stops being viable very quickly. This guide explains how batch PDF redaction works on Mac, why it matters, and how to do it efficiently — without spending hundreds of dollars on Adobe Acrobat Pro.
Batch redaction is not a niche workflow. It comes up in a surprising range of professional contexts:
In each of these cases, the problem is the same: volume. The solution needs to scale.
Redacting one document and redacting two hundred documents are not the same task done more times. They are fundamentally different problems.
Consistency. When you redact manually, one document at a time, you rely on memory and attention to apply the same rules across every file. Did you catch all the phone numbers in document 147 the same way you caught them in document 12? Human memory is not a reliable quality control system at scale.
Time. Even if a single PDF takes only five minutes to redact carefully, 200 files equals more than 16 hours of focused work. That is not a realistic allocation of a compliance officer's time, and it does not account for review.
Human error risk. Fatigue increases error rate. The 180th document you redact in a session is more likely to have a missed name or phone number than the first. In legal and regulatory contexts, a single missed redaction in a production can have serious consequences — it can lead to sanctions, discovery disputes, or exposure of protected information.
Batch redaction addresses all three problems by applying a consistent set of rules automatically across every file in a set. The rules run the same way on file 1 as on file 200.
For more on proper redaction technique, see our guide on how to redact a PDF on Mac without Adobe Acrobat.
macOS Preview gained a built-in redaction feature in macOS Sonoma. It performs true redaction — meaning it permanently removes text from the file structure rather than just drawing a black box over it. For a single document, it works.
The workflow is: open the PDF, go to Tools, select Redact, highlight each piece of sensitive text, then save. Preview warns you that redaction is permanent before writing the file.
The limitation is that every step is manual. Preview has no automatic detection of emails, phone numbers, names, or any other data type. You must read every page, identify sensitive content by eye, and select it. For a 10-page contract, that is manageable. For 200 contracts, it means reading through thousands of pages and making thousands of individual selections — with no guarantee of consistency.
There is also no batch capability. Preview processes one document at a time. You cannot point it at a folder and walk away. Each file must be opened, reviewed, redacted, and saved individually.
The manual approach works for occasional, low-volume use. It is not a solution for teams dealing with regular redaction workloads.
BlurData is a macOS app built specifically for this problem. It automatically detects sensitive data in PDFs and images, supports batch processing of entire folders, and runs fully offline. There is no subscription — it costs $29 as a one-time purchase.
The batch redaction workflow takes four steps:
The key difference from Preview is that BlurData does the finding for you. You are reviewing and approving, not manually hunting through every page of every document.
One of the most useful features for teams handling batch redaction is the ability to define custom detection patterns. BlurData supports regex-based rules, which means you can specify exactly what to look for beyond the built-in data types.
This matters because sensitive data is often organization-specific. An insurance company's claim numbers follow a different format than a law firm's matter numbers. A hospital's patient ID format is unique to that institution. Generic detection catches emails and phone numbers, but it will miss proprietary identifiers unless you tell it what to look for.
Some examples of custom patterns teams commonly define:
EMP-\d{6} to catch IDs in a specific formatOnce you define a custom pattern, it applies to every file in the batch. You define it once, and it runs consistently across 5 files or 500. For a deeper look at building custom patterns, see our guide on custom regex patterns and batch redaction in BlurData.
Applying redactions is only half the job. Before you share or produce a batch of redacted documents, you need to verify that the redactions actually worked. This is especially important when the consequences of a missed redaction are significant.
Here are the checks to run on a sample of your exported files:
Try to select and copy the redacted text. Open a redacted PDF and attempt to click on and highlight text in the areas that should have been redacted. If you can select or copy it, the redaction failed. True redaction removes the text from the file — you should not be able to interact with it at all.
Search for known terms. Use Cmd+F to search for specific words, names, or numbers that you know appeared in the original document and should now be redacted. If the search returns any results in areas that were supposed to be redacted, the content was not removed.
Open the file in a different PDF viewer. Some redaction failures only become visible when a file is opened in a different application. What appears redacted in one viewer may show the underlying text when opened in another. Test with at least one other PDF application.
Spot-check a representative sample. For large batches, you do not need to verify every single page of every file, but you should check a meaningful sample — including files from different parts of the batch, not just the first few. Pay particular attention to files with unusual formatting, scanned pages, or complex layouts.
Check file metadata. Some PDF tools store information about the redaction process in the file's metadata. Inspecting metadata with a tool like ExifTool can confirm whether the file was processed and by which application.
The goal of verification is to confirm that the exported files are safe to share. A few minutes of spot-checking on a batch of 200 files is a reasonable investment compared to the risk of releasing a document with sensitive information intact.
If you are redacting PDFs occasionally and one at a time, macOS Preview is a reasonable free option on Sonoma and later. It performs true redaction and costs nothing.
But if you are dealing with batches of files — whether it is 10 contracts or 500 case files — the manual approach is both inefficient and risky. Inconsistency and missed detections are the predictable result of manual work at scale.
BlurData was built for exactly this use case. Drag a folder, let auto-detection run, review the results, and export. The entire process that would take hours manually can be completed in minutes. It runs entirely offline, so your documents never leave your Mac. And at $29 one-time, it is a fraction of the cost of Adobe Acrobat Pro.
If batch PDF redaction is a regular part of your workflow, the time savings alone justify the cost within the first hour of use. Download BlurData and try it free for 7 days.