Most people "black out" text by drawing a black rectangle over it. That looks finished — but the words underneath are still in the file, ready to be copied, extracted, or uncovered. To black out text so it can't be recovered, you have to remove the words, not just hide them. Here's the difference, the two tools that do it right, and how to confirm the words are actually gone.
When you "black out" text in most PDF tools — drawing a filled black rectangle, or highlighting a passage in black — you aren't deleting anything. You're adding one more layer on top of the page. The original words sit unchanged directly beneath the new shape, fully intact in the file's text layer.
That leftover text comes back out three easy ways. Select and copy grabs the underlying characters no matter what's drawn over them, so the hidden words paste straight into any text editor. "Remove object" or "delete annotation" in any PDF editor lifts the black rectangle off and exposes the page. And text extraction — the routine search engines and screen readers use — reads the characters directly, box or no box. This is exactly how "redacted" court filings and government releases have leaked: the tool drew a box but never deleted what was underneath.
The takeaway is simple: covering text and removing text look identical on screen, but only one is safe to send. A black box is decoration. Real blackout is destruction.
To black out text properly, you need destructive redaction — a process that removes the characters, the underlying objects, and the metadata, so there is literally nothing left under the mark to recover. Two tools do this reliably:
Acrobat Pro's Redact tool genuinely removes the marked content instead of masking it, and its separate Sanitize Document step strips hidden metadata, layers, and scripts. It's the long-standing benchmark, and the right pick if you also need OCR, text editing, or form work in the same file.
The trade-off is cost and setup: a desktop install, an Adobe account, and a subscription around $19.99/month.
BlackoutPDF reaches the same guarantee a different way: it re-renders each page to flat pixels, burns the black boxes into those pixels, and rebuilds a brand-new PDF from the images. Because the output is built from scratch, there's no text layer left under the black and the original metadata doesn't survive — nothing to select, copy, or extract.
It runs 100% in your browser — your file is never uploaded — and it's free for short documents. The honest trade-off: the rasterized output is not text-selectable, which for a blacked-out document is usually exactly what you want, but is wrong if the recipient needs to search the file.
No account, no upload, no install. The whole job is three steps in the browser.
Go to the redactor and choose your file. It loads straight into the page in your browser — nothing is sent to a server, so even a sensitive document never leaves your machine.
Draw a box over each passage you want gone. To catch sensitive data automatically, use Auto-Redact to find SSNs, emails, and phone numbers, and run OCR first if your PDF is a scan so the text is detectable.
Hit export. BlackoutPDF rebuilds each page as pixels with the black burned in and assembles a fresh PDF. The marked words are destroyed, not hidden — and the file downloads straight to your device.
Never trust that a blackout worked because the page looks right. Spend thirty seconds proving it before you send anything. If any of these tests returns the hidden content, the text wasn't removed — do it destructively and try again.
Open the finished file, drag-select across a blacked-out passage (or hit Select All), and paste into a plain text editor. If any "hidden" words appear, the text layer survived and the blackout failed.
Check Document Properties (or "Get Info") for author, title, and history fields. Leftover names, original filenames, or edit history mean metadata wasn't stripped — a separate leak even when the visible page looks clean.
Use any "extract text" or "save as text" feature, or a command-line tool, to pull every character out of the file. A truly blacked-out page yields no recoverable text where the black boxes are. This is the test that catches what the eye and the copy-paste miss.
BlackoutPDF removes the words instead of covering them: pages are re-rendered to pixels and rebuilt into a fresh PDF, so there's no text layer left under the black and the metadata is stripped. It all happens in your browser — your document never leaves your machine. Free for short files; verify the result with the three tests above before you send.
Going deeper: why a black box isn't redaction unpacks how "redacted" documents leak and what true destructive redaction does, and redact a PDF without uploading it explains the no-upload, in-browser architecture in detail. For everything else, see all guides.
Usually not. In most tools, "blacking out" means drawing a black rectangle or highlight over the words — which only adds a layer on top. The original characters stay in the file's text layer, so they can be selected and copied, exposed by deleting the black rectangle as an object, or pulled out with text extraction. To genuinely remove the text you need destructive redaction, which deletes the content itself rather than covering it.
Use a tool that destroys the underlying text rather than masking it. Adobe Acrobat Pro does this with its Redact tool plus the Sanitize Document step. BlackoutPDF does it by re-rendering each page to flat pixels, burning the black boxes into those pixels, and rebuilding a new PDF from the images — entirely in your browser, with nothing uploaded. Because the output has no text layer beneath the black, there is nothing left to select, copy, or extract.
No. A black highlight (or a black-filled rectangle) is a visual overlay — it changes how the page looks but leaves the actual words in the file. Anyone can select beneath it, remove the highlight object, or extract the text. Redaction is the opposite: it permanently removes the marked content and its metadata so nothing recoverable remains. A black highlight that looks identical to a redaction is exactly how documents get leaked.
Run three quick tests on the finished file. First, try to select and copy across the blacked-out areas and paste into a text editor — nothing hidden should appear. Second, open Document Properties to confirm no leftover author, history, or filename metadata. Third, for the strict check, extract all text from the file; a true blackout yields no recoverable text where the black boxes are. If any test surfaces the hidden content, the blackout failed and must be redone destructively.