A black rectangle on a PDF page and a black rectangle on a PNG look identical in a thumbnail. They are not the same object. One is often a drawing instruction sitting on top of a live text stream. The other is replaced image samples with no characters left to select. Mixing those failure modes is how people fear the wrong bug, or ignore the one they actually have.
BBC reporting in January 2019 on a Manafort filing is the public example this page uses: black boxes that still left copy-pasteable text. That is overlay redaction on a document. It is not a screenshot editor. This page is file hygiene, not legal advice, and not a court filing guide.
Overlay instructions versus replaced pixels
A PDF box is frequently a drawing command. The letters remain in the content stream. Search, select, and copy can still return the “hidden” words. A screenshot that you then fill with black in a raster editor replaces samples. There is no text layer to copy unless you later run OCR, and OCR on a solid bar returns nothing useful.
If you screenshot a PDF that was badly overlaid, you may capture the boxes as pixels and still leave the original PDF in the email. The filing is not cleaned because you photographed the page. The PNG might be fine. The attachment list might not.
How to check a PDF box versus a PNG bar
- Open the PDF in a reader. Try to select the “blacked out” line. Search for a word you know was under the box. Copy and paste into a plain text editor. If text comes back, you have the overlay failure BBC described.
- If your job is a Slack snip, stay off the PDF. Paste the screenshot into a raster editor. Paint an opaque fill. Download PNG.
- Open the PNG. Zoom. Invert. Try brightness. You should see a uniform rectangle. If glyphs return, you used a tint, not a fill.
- Check the email or ticket. Send the flattened file. Do not attach the original PDF “for quality” next to the PNG.
Open larger image in a new tabDoes a PNG bar fail the Manafort way?
Not by copy-paste of a text layer. A PNG does not carry a PDF content stream. It can still fail by highlighter tint, by a gap in the bar, by a blur that leaves glyph shape, or by sending the original alongside the export. Those are raster failures. BBC’s Manafort story is the overlay failure. Keep the citation in the overlay bucket.
How to choose a solid fill on images: blur vs black bar. How to keep a lossless copy of that fill: PNG vs JPEG.
If your job is legal PDF redaction
Use a proper redaction tool that removes content streams. Adobe’s help on removing sensitive content is the vendor page to start with: redaction that deletes, not a black square in a consumer PDF app that only paints. Not Markup highlighter on a screenshot of page four. Not “flatten” by printing to a new PDF unless you have verified the text is gone. Verification means try to select, search, and copy, then check the file, not the screen.
Do not screenshot a PDF, bar the image, and call the original filing clean. The original filing is the PDF. The screenshot is a picture of a page. Courts and counterparties get the PDF. Ask counsel which file they are sending. That is still not legal advice. It is “which attachment is in the draft.”
If your job is a Slack snip
Produce a flat PNG with replaced pixels. You are not producing a court PDF. You are producing an image. Do not paste a PDF into Slack and draw a box in a previewer. Export from an editor that bakes the fill. Inspect the download. Do not assume Slack “flattened” a PDF attachment.
Open larger image in a new tabCan OCR bring back a solid bar?
OCR reads glyphs. A uniform rectangle has none. A light smear may have enough shape that a person, or software, can guess a short string. That is the screenshot problem, not the Manafort problem. Solve it with a fill, not with a second PDF box on top of a PNG. PETS 2016 is the leftover-structure paper. It does not turn a solid bar into copy-pasteable text.
What “print to PDF” after drawing boxes can still do
Print-to-PDF can flatten drawings and still keep a text layer, or rasterize the page, depending on the tool. You do not guess. You try select, search, and copy on the output. If text comes back, you have the overlay failure BBC described: boxes that look opaque and are not deletion. If the output is a true raster with a solid fill, you have a picture, and the original PDF may still be sitting in the same email.
Two files, two jobs. Redact the document with a tool that removes streams. Redact the screenshot with replaced pixels. Do not use one as a charm against the other. If counsel only received the PNG, the PDF on your disk is still the filing.
If you can still select the text
The box was paint, not deletion. Use a redaction tool that removes content, or start over from a raster you actually filled. Do not upload the live PDF to a random “black box” website. Do not assume a highlighter in Preview removed the stream. Check select, search, copy. Then check which file is attached.
Two files, two jobs
Overlay PDFs fail by copy-paste. Flattened PNGs fail by tint, gaps, and the wrong attachment. Court-shaped leaks in the news were the first kind. Your Slack snip is the second. If you only needed a chat snip, stay on a raster export and paint there: flatten the bar as PNG in BlurThis.
