{"id":1019,"date":"2026-10-23T17:34:22","date_gmt":"2026-10-23T17:34:22","guid":{"rendered":"http:\/\/jfdi-blog-how-to-redact-a-pdf"},"modified":"2026-10-24T13:38:26","modified_gmt":"2026-10-24T13:38:26","slug":"how-to-redact-a-pdf","status":"publish","type":"post","link":"https:\/\/jfdi.pro\/blog\/how-to-redact-a-pdf\/","title":{"rendered":"How to redact a PDF properly (a black box isn&#8217;t enough)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">To redact a PDF properly, the hidden words have to be <strong>removed from the file<\/strong>, not just covered. A black rectangle, a black highlight or a white box drawn on top hides text from view, but the text is still there underneath, and anyone can select it, copy it and paste it somewhere else. Use a real redaction tool, then check the result before you send it.<\/p>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/jfdi.pro\/pdf\/\">Redact a PDF<\/a><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">The black box mistake keeps happening<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This isn&#8217;t a beginner&#8217;s error. It has caught out lawyers, government departments and newspapers for years:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>January 2019:<\/strong> lawyers for Paul Manafort filed a document in his case with black bars over sensitive passages. A <em>Guardian<\/em> reporter found the text could be copied and pasted into a new document, revealing details about his contacts with Konstantin Kilimnik (<a href=\"https:\/\/www.cjr.org\/analysis\/manafort-mueller-redacted-document-ukraine.php\">Columbia Journalism Review<\/a>).<\/li>\n\n\n\n<li><strong>2014:<\/strong> redactions in a leaked CIA presentation published by <em>The New York Times<\/em> could be bypassed by highlighting and copying, exposing an NSA agent&#8217;s name.<\/li>\n\n\n\n<li><strong>2011:<\/strong> a federal judge&#8217;s opinion in <em>Apple v. Samsung<\/em> had redacted passages that could be copied into a text document.<\/li>\n\n\n\n<li>A 2011 study estimated that &#8220;thousands, and probably tens of thousands&#8221; of documents in the US federal courts&#8217; PACER system had redaction failures.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The last three are from the American Bar Association&#8217;s round-up of <a href=\"https:\/\/www.americanbar.org\/groups\/judicial\/publications\/judges_journal\/2019\/spring\/embarrassing-redaction-failures\/\">embarrassing redaction failures<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Why covering doesn&#8217;t work<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A PDF isn&#8217;t a picture of a page. It&#8217;s a list of instructions: put these words here in this font, draw this shape there, place this image. When you draw a black box, you add one more instruction, <em>draw a black rectangle<\/em>, on top. The instruction that draws the words is untouched, so:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Copy and paste<\/strong> pulls the text from under the box.<\/li>\n\n\n\n<li><strong>Search<\/strong> finds it.<\/li>\n\n\n\n<li><strong>Screen readers<\/strong> read it aloud.<\/li>\n\n\n\n<li><strong>Text extraction<\/strong> by any program, including search engines, sees it.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The same goes for black highlighting in Word before saving as PDF, and for white-out boxes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What proper redaction does<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Real redaction removes the content under the box from the file. In the <a href=\"https:\/\/jfdi.pro\/pdf\/\">JFDI PDF toolkit<\/a>, the <strong>Redact<\/strong> tool works like this:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Open the PDF in the toolkit and go to <strong>Edit &amp; sign<\/strong>.<\/li>\n\n\n\n<li>Choose <strong>Redact<\/strong> (shortcut <strong>X<\/strong>) and drag over every name, number or passage that must go.<\/li>\n\n\n\n<li>Download. Each page with a redaction is rebuilt as a 200 dpi image with the black boxes burned in, so the hidden words no longer exist anywhere in the file.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">The trade-off: the rest of a redacted page can no longer be selected or searched, because the page is now a picture. Pages without redactions stay as normal text. Page numbers and watermarks are added afterwards, so they stay sharp.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nothing is uploaded at any point. The PDF is opened and rebuilt inside your browser, which is the point when the document is confidential.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Don&#8217;t forget the hidden information<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Visible text isn&#8217;t the only thing that leaks. PDFs can carry:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Document details<\/strong>: the author&#8217;s name, the software used, creation and editing dates.<\/li>\n\n\n\n<li><strong>Editing history<\/strong>: some programs save changes by adding to the end of the file, so earlier versions of a page can still be inside.<\/li>\n\n\n\n<li><strong>Attachments, scripts and form data.<\/strong><\/li>\n\n\n\n<li><strong>Text under scans<\/strong>: a scanned page that&#8217;s been through OCR has an invisible text layer behind the image.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">In the toolkit&#8217;s <strong>Finish<\/strong> tab, tick <strong>Remove hidden information<\/strong> before downloading. It strips the author, software, dates, embedded metadata, scripts, attachments and editing history. And check the <strong>file name<\/strong>: &#8220;Smith-v-Jones-settlement-\u00a32.4m.pdf&#8221; can give away what the redactions hide.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">White-out or redact?<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><\/th><th>White-out<\/th><th>Redact<\/th><\/tr><\/thead><tbody><tr><td>Looks like<\/td><td>A white (or coloured) box<\/td><td>A black box<\/td><\/tr><tr><td>The hidden words<\/td><td>Still in the file. Anyone can copy them.<\/td><td>Removed for good<\/td><\/tr><tr><td>Rest of the page<\/td><td>Unchanged<\/td><td>Turned into an image<\/td><\/tr><tr><td>Use it for<\/td><td>Tidying up, hiding a typo, making space for new text<\/td><td>Names, addresses, account numbers, anything confidential<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The toolkit&#8217;s <strong>Change existing text<\/strong> tool also covers the original words rather than removing them, so never use it to remove private information.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Check before you send: five tests<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Select all and copy<\/strong> (Ctrl+A, Ctrl+C) on each redacted page, then paste into a text editor. Nothing hidden should appear.<\/li>\n\n\n\n<li><strong>Search<\/strong> the PDF for a redacted word, such as a surname.<\/li>\n\n\n\n<li><strong>Open it in a different PDF reader<\/strong>: your browser&#8217;s built-in viewer and one other.<\/li>\n\n\n\n<li><strong>Check the document properties<\/strong> (File \u203a Properties in most readers) for the author and title.<\/li>\n\n\n\n<li><strong>Read the file name.<\/strong><\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Common questions<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Can a redaction be undone?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Not when the content has been removed, as above. A drawn box can be &#8220;undone&#8221; by anyone with a PDF editor, by simply deleting the box.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is redacting a scanned document different?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A scan is already a picture, so a black box burned into the image hides it. But scans often have an invisible OCR text layer; a real redaction tool removes that too, which is why the toolkit rebuilds the page.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Does Adobe Acrobat do this properly?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Yes, when you use its Redact tool and apply the redactions; drawing a black shape with its comment tools doesn&#8217;t. The same check above works for any tool.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Related<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/jfdi.pro\/blog\/edit-pdf-without-uploading\/\">How to edit a PDF without uploading it<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jfdi.pro\/blog\/which-online-tools-upload-your-files\/\">Which online file tools upload your files? We checked six<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/jfdi.pro\/help-pdf.html\">The PDF toolkit guide: white-out or redact?<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Drawing a black box over text in a PDF hides it from view but leaves it in the file, where anyone can copy it out. Here&#8217;s how real redaction works, the mistakes that have exposed court filings, and a five-step check.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[47,43,46,45],"class_list":["post-1019","post","type-post","status-publish","format-standard","hentry","category-pdfs","tag-legal","tag-pdf","tag-privacy","tag-redaction"],"_links":{"self":[{"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/posts\/1019","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/comments?post=1019"}],"version-history":[{"count":3,"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/posts\/1019\/revisions"}],"predecessor-version":[{"id":1076,"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/posts\/1019\/revisions\/1076"}],"wp:attachment":[{"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/media?parent=1019"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/categories?post=1019"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jfdi.pro\/blog\/wp-json\/wp\/v2\/tags?post=1019"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}