Why blurring sensitive text isn't enough
Blurred and pixelated text looks hidden, but it often isn't. What visual obscuring actually does to your pixels, why it can be reversed, and what secure redaction means.
6 min read · Reviewed July 2026
Black out text in a screenshot
Posting a screenshot to a bug report, a forum, or a group chat usually means something in it shouldn't be there: an email address, an account number, an API key in a terminal. Drawing a solid black box over it, properly, makes that information actually gone.
The important word is properly. This tool burns the black boxes into brand-new pixels and then re-decodes the output to verify every covered region contains nothing but the fill color. That's a different thing entirely from a black rectangle layered in an editor, which can sometimes be lifted right back off.
Processed locallyIn: PNG, JPEG, WebPOut: PNG, JPEG, WebP
Loading tool…
This is Redact Image preconfigured for this task — open the full tool for every option.
How it works
Drop or select an image — it opens locally in the editor.
Draw rectangles over sensitive content in Secure Black, Secure White, or Custom Solid mode.
Optionally switch to Blur or Pixelate for non-confidential cosmetic obscuring (a persistent warning explains the difference).
Review the region list, then export. The final image is rasterized into brand-new pixels.
The tool re-decodes the output and verifies every secure region contains only replacement pixels before offering the download.
What the tool does
- Secure Black, Secure White, and Custom Solid redaction modes
- Blur and Pixelate visual-obscuring modes, clearly labelled as non-secure
- Editable region list with per-region mode, delete, and one-click convert-to-secure
- One-click conversion of all blur/pixelate regions to secure solid redaction
- Pixel-level verification that secure regions contain only the replacement color
- Metadata (EXIF/GPS) is not carried into the exported image
How the result is verified
After export the tool decodes the output bytes again and samples every secure region to confirm the pixels exactly match the replacement color, and confirms the output carries no EXIF metadata. If any check fails, the download is blocked and marked Failed verification.
Frequently asked questions
Is a black box in a normal editor not enough?
Depends on the editor. Tools that save layers, or PDFs with rectangles drawn over text, can expose the content underneath to anyone who removes the layer. This tool flattens everything into new pixels and then verifies the covered areas, so there's no underneath.
Can I redact several areas at once?
Yes, draw as many regions as you need. Each one is listed with its mode, and every solid region gets pixel-verified at export.
Does my screenshot get uploaded?
No. The editor, the export, and the verification all run in your browser tab. The network panel will show nothing carrying your image.
Understand the format
Technical guidance for choosing settings and reviewing the result.
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